Sample records for at1 receptor blockade

  1. Prevention of atherosclerosis by specific AT1-receptor blockade with candesartan cilexetil

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    Vasilios Papademetriou


    Full Text Available Several studies indicate that blockade of the renin-angiotensin-aldosterone system (RAAS can prevent atherosclerosis and vascular events, but the precise mechanisms involved are still unclear. In this study, we investigated the effect of the AT 1-receptor blocker, candesartan, in the prevention of atherosclerosis in Watanabe heritable hyperlipidaemic (WHHL rabbits and also the effect of AT1-receptor blockade in the uptake of oxidised LDL by macrophage cell cultures. In the first set of experiments, 12 WHHL rabbits were randomly assigned to three groups: placebo, atenolol 5 mg/kg daily or candesartan 2 mg/kg daily for six months. Compared with controls and atenolol-treated rabbits, candesartan treatment resulted in a significant 50—60% reduction of atherosclerotic plaque formation and a 66% reduction in cholesterol accumulation in the thoracic aorta.Studies in macrophage cultures indicated that candesartan prevented uptake of oxidised LDL-(oxLDL-cholesterol by cultured macrophages. Candesartan inhibited the uptake of oxLDL in a dose-dependent manner, reaching a maximum inhibition of 70% at concentrations of 5.6 µg/ml. Further studies in other animal models and well-designed trials in humans are warranted to further explore the role of AT1-receptor blockade in the prevention of atherosclerosis.

  2. AT1 receptor blockade regulates the local angiotensin II system in cerebral microvessels from spontaneously hypertensive rats. (United States)

    Zhou, Jin; Pavel, Jaroslav; Macova, Miroslava; Yu, Zu-Xi; Imboden, Hans; Ge, Linna; Nishioku, Tsuyoshi; Dou, Jingtao; Delgiacco, Elizabeth; Saavedra, Juan M


    Blockade of angiotensin II AT1 receptors in cerebral microvessels protects against brain ischemia and inflammation. In this study, we tried to clarify the presence and regulation of the local renin-angiotensin system (RAS) in brain microvessels in hypertension. Spontaneously hypertensive rats (SHR) and Wistar Kyoto (WKY) controls were treated with an AT1 receptor antagonist (candesartan, 0.3 mg/kg per day) via subcutaneous osmotic minipumps for 4 weeks. The expression and localization of RAS components and the effect of AT1 receptor blockade were assessed by Affymetrix microarray, qRT-PCR, Western blots, immunohistochemistry and immunofluorescence. We found transcripts of most of RAS components in our microarray database, and confirmed their expression by qRT-PCR. Angiotensinogen (Aogen), angiotensin-converting enzyme (ACE) and AT1 receptors were localized to the endothelium. There was no evidence of AT2 receptor localization in the microvascular endothelium. In SHR, (pro)renin receptor mRNA and AT1 receptor mRNA and protein expression were higher, whereas Aogen, ACE mRNA and AT2 receptor mRNA and protein expression were lower than in WKY rats. Candesartan treatment increased Aogen, ACE and AT2 receptor in SHR, and increased ACE and decreased Aogen in WKY rats, without affecting the (pro)renin and AT1 receptors. Increased (pro)renin and AT1 receptor expression in SHR substantiates the importance of the local RAS overdrive in the cerebrovascular pathophysiology in hypertension. AT1 receptor blockade and increased AT2 receptor stimulation after administration of candesartan may contribute to the protection against brain ischemia and inflammation.

  3. Angiotensin II AT1 receptor blockade abolishes brain microvascular inflammation and heat shock protein responses in hypertensive rats. (United States)

    Zhou, Jin; Ando, Hiromichi; Macova, Miroslava; Dou, Jingtao; Saavedra, Juan M


    Endothelial dysfunction and inflammation enhance vulnerability to hypertensive brain damage. To explore the participation of Angiotensin II (Ang II) in the mechanism of vulnerability to cerebral ischemia during hypertension, we examined the expression of inflammatory factors and the heat shock protein (HSP) response in cerebral microvessels from spontaneously hypertensive rats and their normotensive controls, Wistar Kyoto rats. We treated animals with vehicle or the Ang II AT(1) receptor antagonist candesartan, 0.3 mg/kg/day, via subcutaneously implanted osmotic minipumps for 4 weeks. Spontaneously hypertensive rats expressed higher Angiotensin II AT(1) receptor protein and mRNA than normotensive controls. Candesartan decreased the macrophage infiltration and reversed the enhanced tumor necrosis factor-alpha and interleukin-1beta mRNA and nuclear factor-kappaB in microvessels in hypertensive rats. The transcription of many HSP family genes, including HSP60, HSP70 and HSP90, and heat shock factor-1 was higher in hypertensive rats and was downregulated by AT(1) receptor blockade. Our results suggest a proinflammatory action of Ang II through AT(1) receptor stimulation in cerebral microvessels during hypertension, and very potent antiinflammatory effects of the Ang II AT(1) receptor antagonist. These compounds might be considered as potential therapeutic agents against ischemic and inflammatory diseases of the brain.

  4. Glomerular and tubular function during AT1 receptor blockade in pigs with neonatal induced partial ureteropelvic obstruction

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    Eskild-Jensen, Anni; Thomsen, Karsten; Rungø, Christine


    and in the present study we examined the effects of chronic AT1 receptor blockade using CV-11974 (0.12 mg/h candesartan from age 23 to 30 days) on kidney function development after PUUO was induced in 2-day-old piglets. Moreover, the effect of superimposed acute NO inhibition using N(G)-nitro-l-arginine methyl ester...... (l-NAME; 15 mg/kg) was examined to identify if this has diagnostic potential. PUUO significantly increased GFR in the nonobstructed contralateral kidney independent of candesartan. In candesartan-treated piglets, the l-NAME-induced GFR reduction seen in normal and nonobstructed kidneys was absent...... by PUUO evidenced by an increased fractional excretion of sodium which was enhanced by candesartan treatment. In conclusion, our findings suggest that the counterbalance between AT1 receptor-mediated vasoconstriction and NO-mediated vasodilatation which maintain GFR in normal young porcine kidneys...

  5. AT1 receptor blockade attenuates insulin resistance and myocardial remodeling in rats with diet-induced obesity.

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    Silvio A Oliveira-Junior

    Full Text Available BACKGROUND: Although obesity has been associated with metabolic and cardiac disturbances, the carrier mechanisms for these responses are poorly understood. This study analyzed whether angiotensin II blockade attenuates metabolic and cardiovascular disorders in rats with diet-induced obesity. MATERIAL AND METHODS: Wistar-Kyoto (n = 40 rats were subjected to control (C; 3.2 kcal/g and hypercaloric diets (OB; 4.6 kcal/g for 30 weeks. Subsequently, rats were distributed to four groups: C, CL, OB, and OBL. L groups received Losartan (30 mg/kg/day for five weeks. After this period we performed in vivo glucose tolerance and insulin tolerance tests, and measured triacylglycerol, insulin, angiotensin-converting enzyme activity (ACE, and leptin levels. Cardiovascular analyzes included systolic blood pressure (SBP, echocardiography, myocardial morphometric study, myosin heavy chain composition, and measurements of myocardial protein levels of angiotensin, extracellular signal-regulated (ERK1/2, c-Jun amino-terminal kinases (JNK, insulin receptor subunit β (βIR, and phosphatidylinositol 3-kinase (PI3K by Western Blot. RESULTS: Glucose metabolism, insulin, lipid, and ACE activity disorders observed with obesity were minimized by Losartan. Moreover, obesity was associated with increased SBP, myocardial hypertrophy, interstitial fibrosis and improved systolic performance; these effects were also minimized with Losartan. On a molecular level, OB exhibited higher ERK, Tyr-phosphorylated βIR, and PI3K expression, and reduced myocardial angiotensin and JNK expression. ERK and JNK expression were regulated in the presence of Losartan, while angiotensin, Tyr-βRI, total and Tyr-phosphorylated PI3K expression were elevated in the OBL group. CONCLUSION: Angiotensin II blockade with Losartan attenuates obesity-induced metabolic and cardiovascular changes.

  6. Protective Effects of Angiotensin II AT1 Receptors Blockade against Brain Injury in Experimental Model of Stroke in Rat

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    Hamdollah Panahpour


    Full Text Available Background & objectives: Ischemic stroke remains the third leading cause of invalidism and death in industrialized countries. It is suggested that renin–angiotensin system (RAS may contribute in stroke related pathogenic mechanisms and involve in the ischemic brain damage. This study designed to investigate the role of angiotensin II (Ang II in conjunction with AT1 receptors in treatment of the brain injuries following transient focal cerebral ischemia in rats.   Methods: Forty eight male Sprague-Dawley rats were studied in four groups. Sham group, ischemic control group and two ischemic groups that received candesartan (0.1mg/kg, or 0.5mg/kg at the beginning of reperfusion period. Transient focal cerebral ischemia was induced by 60 minutes occlusion of the middle cerebral artery, followed by 24 hours reperfusion. At the end of the reperfusion period, neurological deficit score (NDS was performed. Total cortical and striatal infarct volumes were determined using triphenyltetrazolium chloride (TTC staining technique.   Results: Animals in sham operated group had normal motor function and no ischemic lesions were observed in cortical or striatal regions. Occurring ischemia in ischemic control group that received vehicle produced considerable infarction in cortex (253±15mm3 and striatum (92±7mm3, as well as these animals had sever impaired motor dysfunctions. Blocking of AT1 receptors with candesartan (0.1mg/kg or 0.5mg/kg improved neurological outcome and significantly lowered cortical and striatal infarct volumes relative to ischemic control group.   Conclusion: The findings of the present study indicated that stimulation of AT1 receptors by Ang II involved in ischemia/reperfusion injuries and blocking of AT1 receptors can decrease ischemic brain injury and improve neurological outcome.

  7. Angiotensin II AT1 receptor blockade decreases vasopressin-induced water reabsorption and AQP2 levels in NaCl-restricted rats

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    Kwon, Tae-Hwan; Nielsen, Jakob; Knepper, M.A.


    Vasopressin and ANG II, which are known to play a major role in renal water and sodium reabsorption, are mainly coupled to the cAMP/PKA and phosphoinositide pathways, respectively. There is evidence for cross talk between these intracellular signaling pathways. We therefore hypothesized...... that vasopressin-induced water reabsorption could be attenuated by ANG II AT1 receptor blockade in rats. To address this, three protocols were used: 1) DDAVP treatment (20 ng/h sc for 7 days, n = 8); 2) DDAVP (20 ng/h sc for 7 days) and candesartan (1 mg·kg−1·day−1 sc for 7 days) cotreatment (n = 8); and 3...... receptor blockade in DDAVP-treated rats was associated with decreased urine concentration and decreased AQP2 and AQP1 expression. Moreover, FENa was increased in parallel with decreased expression of NHE3, NCC, and Na-K-ATPase. These results suggest that ANG II AT1 receptor activation plays a significant...

  8. The effect of AT1 receptor blockade on bax and bcl-2 expression in bleomycin-induced pulmonary fibrosis

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    L Safaeian


    Full Text Available ABSTRACT Background and the purpose of the study: Recent studies have indicated the role of apoptosis and angiotensin in the pathogenesis of bleomycin induced-pulmonary fibrosis. Losartan, an angiotensin type 1 receptor (AT1R antagonist, has ameliorated apoptosis and fibrosis from bleomycin. In this study, alterations in the expression of apoptosis-regulatory genes (bcl-2 and bax were investigated in different cells of lung tissue of mice treated with bleomycin in the presence of losartan. Methods: Losartan (10 mg/kg, i.p. was given to mice two days before administration of bleomycin (3 U/kg and throughout the test period. After two weeks, lung tissues of mice were evaluated for fibrosis by biochemical measurement of collagen deposition and semiquantitative analysis of pathological changes of the lung. The expression of bcl-2 and bax was assessed by immunohistochemical assay using biotin-streptavidin staining method on paraffin-embedded lung tissues. Results and major conclusion: Pre-treatment with losartan significantly (P < 0.05 reduced the increase in lung collagen content and also inhibited the histological changes induced by bleomycin. Immunohistochemical studies showed that losartan significantly (P < 0.05 reduced the bax/bcl-2 expression ratio in the alveolar epithelial cells, lymphocytes, macrophages and interstitial myofibroblasts. Losartan also inhibited the bcl-2 upregulation which was educed by bleomycin in neutrophils. By reduction of bax/bcl-2 ratio as a determinant of susceptibility of a cell to apoptosis, losartan exerted protective effects on the alveolar epithelial cells that may be important in the amelioration of pulmonary fibrosis. These results may help to better understanding of the role of angiotensin II and apoptosis in pulmonary fibrosis.

  9. AT1 receptor blockade alters nutritional and biometric development in obesity-resistant and obesity-prone rats submitted to a high fat diet

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    Pauline M Smith


    Full Text Available Obesity is a chronic metabolic condition with important public health implications associated with numerous co-morbidities including cardiovascular disease, insulin resistance, and hypertension. The renin angiotensin system (RAS, best known for its involvement in cardiovascular control and body fluid homeostasis has, more recently, been implicated in regulation of energy balance. Interference with the RAS (genetically or pharmacologically has been shown to influence body weight gain. In this study we investigated the effects of systemic AT1 receptor blockade using losartan on ingestive behaviors and weight gain in diet induced obese (DIO rats. Prior to losartan administration (30mg/kg/day body weight gain remained constant within the DIO animals (3.6 ± 0.3g/day, n=8, diet resistant (DR animals (2.1 ± 0.6g/day, n=8 and in the age matched chow fed control (CHOW animals (2.8 ± 0.3g/day, n=8, Losartan administration abolished body weight gain in animals fed a high fat diet (DIO: -0.4 ± 0.7g/day, n=8; and DR: -0.8 ± 0.3g/day, n=8 while chow fed animals continued to gain weight (2.2 ± 0.3g/day, n=8 as they had previously to oral administration of losartan. This decrease in daily body weight gain was accompanied by a decrease in food intake in the high fat diet fed animals. Following the removal of losartan, both the DIO and DR animals again showed daily increases in body weight gain and food intake which were similar to control values. Our data demonstrate that oral losartan administration attenuates body weight gain in animals fed a HFD whether the animal is obese (DIO or not (DR while having no effect on body weight gain in age matched chow fed animals suggesting a protective effect of losartan against body weight gain while on a HFD.

  10. Blockade of angiotensin AT1-receptors in the rostral ventrolateral medulla of spontaneously hypertensive rats reduces blood pressure and sympathetic nerve discharge

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    Andrew M Allen


    Full Text Available Microinjections of angiotensin II (Ang II into the rostral ventrolateral medulla (RVLM induce a sympathetically-mediated increase in blood pressure (BP, through an interaction with AT1-receptors. Under basal conditions in anaesthetised animals, microinjections of AT 1-receptor antagonists into the RVLM have little, or no effect on BP, suggesting that the angiotensin input to this nucleus is not tonically active. In contrast, microinjections of AT1-receptor antagonists into the RVLM of sodium-deplete rats and TGR(mRen227 rats, induce a depressor response through sympatho-inhibition. This indicates that when the renin-angiotensin system is activated, angiotensin can act in the RVLM to support sympathetic nerve discharge and BP. This study examined whether angiotensin inputs to the RVLM are activated in the spontaneously hypertensive rat — a pathophysiological model which displays increases in both brain angiotensin levels and sympathetic nerve activity. Bilateral microinjections of the AT 1-receptor antagonist candesartan cilexetil, (1 nmol in 100 nl, into the RVLM of the spontaneously hypertensive rat induced a significant decrease in lumbar sympathetic nerve discharge (-18±2% and BP (140±6 to 115±6 mmHg. In contrast, similar microinjections in the Wistar-Kyoto (WKY rat had no effect on BP or sympathetic nerve discharge. These results are interpreted to suggest that Ang II inputs to the RVLM are activated in the spontaneously hypertensive rat to maintain an elevated level of sympathetic nerve discharge, even in the face of increased BP.

  11. Effects of AT1 Receptor Blockade on Plasma Thromboxane A2 (TXA2 Level and Skin Microcirculation in Young Healthy Women on Low Salt Diet

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    Ana Cavka


    Full Text Available Objective: To determine the effect of AT1 receptor antagonism on skin microcirculation and plasma level of thromboxane A2 (TXA2. Methods: Healthy women (n=20 maintained 7 days low salt (LS diet (intake 2 metabolite thromboxane B2 (TXB2 and plasma renin activity (PRA aldosterone concentration, electrolytes (Na+, K+, as well as blood pressure and heart rate were determined before and after study protocols. Results: PRA and aldosterone increased significantly after 7 days of both LS diet and LS diet+losartan. LS diet or LS diet+losartan administrations had no significant effect on post-occlusion hyperemia While there was no change in TXB2 after LS diet TXB2 significantly increased after one week of LS+losartan compared to control levels (cTXB2 pg/mL control 101±80 vs. LS diet+losartan 190±116, pConclusion: These data suggest that inhibition of AT1 receptors could lead to activation of AT2 receptors, which maintain hyperemia, despite the increased level of vasoconstrictor TXA2. These findings also suggest an important role of crosstalk between renin-angiotensin system (RAS and arachidonic acid metabolites in the regulation of microcirculation under physiological conditions.

  12. Impaired vascular contractility and aortic wall degeneration in fibulin-4 deficient mice: effect of angiotensin II type 1 (AT1 receptor blockade.

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    Els Moltzer

    Full Text Available Medial degeneration is a key feature of aneurysm disease and aortic dissection. In a murine aneurysm model we investigated the structural and functional characteristics of aortic wall degeneration in adult fibulin-4 deficient mice and the potential therapeutic role of the angiotensin (Ang II type 1 (AT(1 receptor antagonist losartan in preventing aortic media degeneration. Adult mice with 2-fold (heterozygous Fibulin-4(+/R and 4-fold (homozygous Fibulin-4(R/R reduced expression of fibulin-4 displayed the histological features of cystic media degeneration as found in patients with aneurysm or dissection, including elastin fiber fragmentation, loss of smooth muscle cells, and deposition of ground substance in the extracellular matrix of the aortic media. The aortic contractile capacity, determined by isometric force measurements, was diminished, and was associated with dysregulation of contractile genes as shown by aortic transcriptome analysis. These structural and functional alterations were accompanied by upregulation of TGF-β signaling in aortas from fibulin-4 deficient mice, as identified by genome-scaled network analysis as well as by immunohistochemical staining for phosphorylated Smad2, an intracellular mediator of TGF-β. Tissue levels of Ang II, a regulator of TGF-β signaling, were increased. Prenatal treatment with the AT(1 receptor antagonist losartan, which blunts TGF-β signaling, prevented elastic fiber fragmentation in the aortic media of newborn Fibulin-4(R/R mice. Postnatal losartan treatment reduced haemodynamic stress and improved lifespan of homozygous knockdown fibulin-4 animals, but did not affect aortic vessel wall structure. In conclusion, the AT(1 receptor blocker losartan can prevent aortic media degeneration in a non-Marfan syndrome aneurysm mouse model. In established aortic aneurysms, losartan does not affect aortic architecture, but does improve survival. These findings may extend the potential therapeutic

  13. Influence of Angiotensin II Subtype 2 Receptor (AT2R Antagonist, PD123319, on Cardiovascular Remodelling of Aged Spontaneously Hypertensive Rats during Chronic Angiotensin II Subtype 1 Receptor (AT1R Blockade

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    Emma S. Jones


    Adult (20 weeks and senescent (20 months spontaneously hypertensive rats (SHRs were treated with either the AT1R antagonist, candesartan cilexetil (2 mg/kg/day, the AT2R antagonist, PD123319 (10 mg/kg/day, or a combination of the 2 compounds. Mean arterial pressure (MAP and left ventricular volume were markedly decreased by candesartan cilexetil, however, simultaneous treatment with PD123319 had no additional effect on either parameter. Perivascular fibrosis was significantly reduced by candesartan cilexetil in aged animals only, and this effect was reversed by concomitant PD123319 administration. Vascular hypertrophy was reduced by candesartan cilexetil, and these effects were reversed by simultaneous PD123319. These results suggest that AT2R stimulation does not significantly influence the antihypertensive effect of chronic AT1R blockade, but plays a role in the regulation of vascular structure. The severe degree of cardiac perivascular fibrosis in senescent animals was regressed by AT1R blockade and this effect was reversed by simultaneous AT2R inhibition, demonstrating an antifibrotic role of AT2R stimulation in the aging hypertensive heart.

  14. Metabolic effects of an AT1-receptor blockade combined with HCTZ in cardiac risk patients: a non interventional study in primary care

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    Schönrock Eleonore


    Full Text Available Abstract Background The reduction of blood pressure alone does not eliminate the increased risk of arterial hypertension. Whilst concomitant metabolic risk factors have been shown to be responsible, the available pharmacotherapy has differential effects on these metabolic risk factors. For example, diuretics and betablockers worsen glucose metabolism, hence the starting point of the current subanalysis of the CHILI (Candesartan in patients with HIgher cardiovascuLar rIsk study was the assumption that an angiotensin receptor blocker may counterbalance the metabolic effects of a low dose diuretic in patients with several metabolic risk factors. Methods The present study was performed as a non-interventional observational study in Germany. Patients with previously uncontrolled hypertension with at least one further risk factor in which physicians deemed a treatment with 16 mg Candesartan/12.5 mg HCTZ to be necessary were included. The risk factors were calculated in patient subgroups with diabetes, the metabolic syndrome (MetSyn and neither condition (control. The risk of cardiovascular mortality within the next 10 years was calculated using the SCORE algorithm of the ESC. Results Between August 2006 and February 2007 a total of 3,787 patients were included into the non-interventional trial. Patients were 62.2 ± 11.3 years old, 48.1% were female, 97.5% had at least one additional risk factor. Blood pressure was reduced by -27.2/-13.4 mmHg with only minor non significant variations between patient groups. Waist circumference was reduced (P Conclusion The present study demonstrates that a 16 mg candesartan/12.5 mg HCTZ based treatment results in a pronounced blood pressure reduction and was associated with a favourable change in metabolic risk factors such as HDL cholesterol, triglycerides and blood glucose. These data indicate that metabolic effects observed in clinical trials like ALPINE, SCOPE or CHARM can also be observed in an unselected

  15. AT1R blockade in adverse milieus: role of SMRT and corepressor complexes. (United States)

    Singh, Tejinder; Ayasolla, Kamesh; Rai, Partab; Chandel, Nirupama; Haque, Shabirul; Lederman, Rivka; Husain, Mohammad; Vethantham, Vasupradha; Chawla, Amrita; Vashistha, Himanshu; Saleem, Moin A; Ding, Guohua; Chander, Praveen N; Malhotra, Ashwani; Meggs, Leonard G; Singhal, Pravin C


    ANG II type 1 receptor blockade (AT1R-BLK) is used extensively to slow down the progression of proteinuric kidney diseases. We hypothesized that AT1R-BLK provides podocyte protection through regulation of silencing mediator of retinoic acid and thyroid hormone receptor (SMRT) and vitamin D receptor (VDR) expression under adverse milieus such as high glucose and human immunodeficiency virus infection. Both AT1R-BLK and VDR agonists (VDAs) stimulated VDR complex formation that differed not only in their composition but also in their functionality. AT1R-BLK-induced VDR complexes contained predominantly unliganded VDR, SMRT, and phosphorylated histone deacetylase 3, whereas VDA-VDR complexes were constituted by liganded VDR and CREB-binding protein/p300. AT1R-BLK-induced complexes attenuated podocyte acetyl-histone 3 levels as well as cytochrome P-450 family 24A1 expression, thus indicating their deacetylating and repressive properties. On the other hand, VDA-VDR complexes not only increased podocyte acetyl-histone 3 levels but also enhanced cytochrome P-450 family 24A1 expression, thus suggesting their acetylating and gene activation properties. AT1R-BLK- induced podocyte SMRT inhibited expression of the proapoptotic gene BAX through downregulation of Wip1 and phosphorylation of checkpoint kinase 2 in high-glucose milieu. Since SMRT-depleted podocytes lacked AT1R-BLK-mediated protection against DNA damage, it appears that SMRT is necessary for DNA repairs during AT1R-BLK. We conclude that AT1R-BLK provides podocyte protection in adverse milieus predominantly through SMRT expression and partly through unliganded VDR expression in 1,25(OH)2D-deficient states; on the other hand, AT1R-BLK contributes to liganded VDR expression in 1,25(OH)2D-sufficient states. Copyright © 2015 the American Physiological Society.

  16. Surviving rat distal tubule bicarbonate reabsorption: effects of chronic AT(1) blockade. (United States)

    Levine, D Z; Iacovitti, M; Luck, B; Hincke, M T; Burns, K D; Fryer, J N


    To determine the in vivo effects of chronic ANG II type 1 (AT(1))-receptor blockade by losartan (Los) on enhanced unidirectional bicarbonate reabsorption (J(HCO(3))) of surviving distal tubules, nephrectomized rats drank either water or a solution of Los, 7 days before microperfusion. J(HCO(3)) was suppressed by 50% after Los without further reduction by 5 nM concanamycin A (Conc), suggesting that Los suppresses all Conc-sensitive H(+)-ATPase pumping. Indeed, ultrastructural analysis of A-type intercalated cells revealed a 50% reduction of H(+)-ATPase immunogold labeling of the apical plasma membrane, whereas Western blotting showed that H(+)-ATPase protein levels were also reduced by one-half by Los treatment. To identify other transporters sustaining J(HCO(3)), we perfused three inhibitors simultaneously [5-(N, N-dimethyl) amiloride hydrochloride, Conc, Schering 28080] with or without prior Los treatment: J(HCO(3)) was unchanged despite marked reduction of water reabsorption. We conclude enhanced distal tubule J(HCO(3)) of surviving nephrons is largely mediated by AT(1) receptor-dependent synthesis and insertion of apical H(+)-ATPase pumps in A-type intercalated cells.

  17. Effects of angiotensin II and angiotensin II type 1 receptor blockade on neointimal formation after stent implantation

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    Groenewegen, Hendrik C.; van der Harst, Pim; Roks, Anton J. M.; Buikema, Hendrik; Zijlstra, Felix; van Gilst, Wiek H.; de Smet, Bart J. G. L.


    Background: To evaluate the effect of supraphysiological levels of angiotensin II and selective angiotensin II type 1 receptor ( AT1-receptor) blockade on neointimal formation and systemic endothelial function after stent implantation in the rat abdominal aorta. Methods: Male Wistar rats were

  18. Inhibition of (prorenin Receptor Contributes to Renoprotective Effects of Angiotensin II Type 1 Receptor Blockade in Diabetic Nephropathy

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    Lin Zhang


    Full Text Available Aims: Renal renin-angiotensin system (RAS plays a pivotal role in the development of diabetic nephropathy (DN. Angiotensin II (Ang II type 1 receptor (AT1R blockade elevates (prorenin, which may bind to (prorenin receptor (PRR and exert receptor-mediated, angiotensin-independent profibrotic effects. We therefore investigated whether PRR activation leads to the limited anti-fibrotic effects of AT1R blockade on DN, and whether PRR inhibition might ameliorate progression of DN.Methods: To address the issue, the expression of RAS components was tested in different stages of streptozotocin (STZ-induced diabetic rats (6, 12, and 24 weeks and 6-week AT1R blockade (losartan treated diabetic rats. Using the blocker for PRR, the handle region peptide (HRP of prorenin, the effects of PRR on high glucose or Ang II-induced proliferative and profibrotic actions were evaluated by measurement of cell proliferation, matrix metalloproteinase-2 (MMP-2 activity, activation of extracellular signal-regulated kinase 1/2 (ERK1/2 and transforming growth factor-β1 (TGF-β1 expression in rat mesangial cells (MCs.Results: PRR was downregulated in the kidneys of different stages of diabetic rats (6, 12, and 24 weeks. Moreover, 6-week losartan treatment further suppressed PRR expression via upregulating AT2R, and ameliorated diabetic renal injury. HRP inhibited high glucose and Ang II-induced proliferative and profibrotic effects in MCs through suppressing TGF-β1 expression and activating MMP-2. Meanwhile, HRP enhanced losartan's anti-fibrotic effects through further inhibiting phosphorylation of ERK1/2 and TGF-β1 expression. Moreover, the inhibitive effect of HRP on Ang II-induced TGF-β1 expression depended on the regulation of PRR expression by AT2R.Conclusions: Our findings suggest that inhibition of PRR contributes to renoprotection against diabetic nephropathy by AT1R blockade.

  19. Functionally Selective AT(1) Receptor Activation Reduces Ischemia Reperfusion Injury

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    Hostrup, Anders; Christensen, Gitte Lund; Bentzen, Bo Hjort


    Angiotensin II (AngII) is a key peptide in cardiovascular homeostasis and is a ligand for the Angiotensin II type 1 and 2 seven transmembrane receptors (AT(1)R and AT(2)R). The AT(1 )receptor is a seven-transmembrane (7TM) G protein-coupled receptor (GPCR) mediating the majority of the physiologi...

  20. AT1 receptor signaling pathways in the cardiovascular system. (United States)

    Kawai, Tatsuo; Forrester, Steven J; O'Brien, Shannon; Baggett, Ariele; Rizzo, Victor; Eguchi, Satoru


    The importance of the renin angiotensin aldosterone system in cardiovascular physiology and pathophysiology has been well described whereas the detailed molecular mechanisms remain elusive. The angiotensin II type 1 receptor (AT1 receptor) is one of the key players in the renin angiotensin aldosterone system. The AT1 receptor promotes various intracellular signaling pathways resulting in hypertension, endothelial dysfunction, vascular remodeling and end organ damage. Accumulating evidence shows the complex picture of AT1 receptor-mediated signaling; AT1 receptor-mediated heterotrimeric G protein-dependent signaling, transactivation of growth factor receptors, NADPH oxidase and ROS signaling, G protein-independent signaling, including the β-arrestin signals and interaction with several AT1 receptor interacting proteins. In addition, there is functional cross-talk between the AT1 receptor signaling pathway and other signaling pathways. In this review, we will summarize an up to date overview of essential AT1 receptor signaling events and their functional significances in the cardiovascular system. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Cerebrovascular angiotensin AT1 receptor regulation in cerebral ischemia

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    Edvinsson, L.


    The mechanism behind the positive response to the inhibition of the angiotensin II receptor AT(1) in conjunction with stroke is elusive. Here we demonstrate that cerebrovascular AT(1) receptors show increased expression (upregulation) after cerebral ischemia via enhanced translation. This enhanced...

  2. Influence of antiseptics on microcirculation after neuronal and receptor blockade. (United States)

    Goertz, Ole; Hirsch, Tobias; Ring, Andrej; Muehlberger, Thomas; Steinau, Hans U; Tilkorn, Daniel; Lehnhardt, Marcus; Homann, Heinz H


    The topical application of the antiseptics octenidine and polyhexanide on wounds seems to improve microcirculation. These two antiseptics were tested in combination with neuronal inhibition and sympathethic receptor blockade to verify these findings, explore the influence of β blockers on these microcirculative effects, and find out the principle of operation. Investigations were carried out on a standardised cremaster muscle model in rats (n = 66). The tested antiseptics, octenidine and polyhexanide were investigated alone (n = 12) and in combination with bupivacaine (n = 12), metoprolol (n = 12), phentolamine (n = 12) and surgical denervation (n = 12). Physiological saline was used for control (n = 6). The arteriolar diameter and functional capillary density (FCD) were investigated via trans-illumination microscopy before, as well as 60 and 120 minutes after application. Polyhexanide caused a significant increase in arteriolar diameter (86·5 ± 3·8 µm versus 100·0 ± 3·6 µm) and, like octenidine (7·2 ± 0·7 n/0·22 mm(2) versus 11·6 ± 0·6 n/0·22 mm(2) ), in FCD (9·2 ± 0·5 versus 12·6 ± 0·9) as well. When the antiseptics are used in combination with bupivacaine, metoprolol, phentolamine or surgical sympathectomy, these effects were eliminated or inverted. Assessing the results of the different blockades in combination with polyhexanide, we surmise that the antiseptic polyhexanide acts on the microcirculation mainly by blocking α receptors. This study shows that polyhexanide and octenidine improve muscular perfusion. Interestingly, the benefit of polyhexanide and octenidine on muscular perfusion is eliminated when the antiseptics are combined with other vasoactive agents, especially β blockers. © 2011 The Authors. © 2011 Blackwell Publishing Ltd and Inc.

  3. Partial neuromuscular blockade in humans enhances muscle blood flow during exercise independently of muscle oxygen uptake and acetylcholine receptor blockade

    DEFF Research Database (Denmark)

    Hellsten, Ylva; Krustrup, Peter; Iaia, F Marcello


    This study examined the role of acetylcholine for skeletal muscle blood flow during exercise by use of the competitive neuromuscular blocking agent cisatracurium in combination with the acetylcholine receptor blocker glycopyrrone. Nine healthy male subjects performed a 10-min bout of one-legged k......This study examined the role of acetylcholine for skeletal muscle blood flow during exercise by use of the competitive neuromuscular blocking agent cisatracurium in combination with the acetylcholine receptor blocker glycopyrrone. Nine healthy male subjects performed a 10-min bout of one....... The enhanced exercise hyperemia during partial neuromuscular blockade may be related to a greater recruitment of fast-twitch muscle fibres. Key words: blood flow, neuromuscular blockade, exercise, skeletal muscle....

  4. The physiological role of AT1 receptors in the ventrolateral medulla

    Directory of Open Access Journals (Sweden)

    T. Tagawa


    Full Text Available Neurons in the rostral and caudal parts of the ventrolateral medulla (VLM play a pivotal role in the regulation of sympathetic vasomotor activity and blood pressure. Studies in several species, including humans, have shown that these regions contain a high density of AT1 receptors specifically associated with neurons that regulate the sympathetic vasomotor outflow, or the secretion of vasopressin from the hypothalamus. It is well established that specific activation of AT1 receptors by application of exogenous angiotensin II in the rostral and caudal VLM excites sympathoexcitatory and sympathoinhibitory neurons, respectively, but the physiological role of these receptors in the normal synaptic regulation of VLM neurons is not known. In this paper we review studies which have defined the effects of specific activation or blockade of these receptors on cardiovascular function, and discuss what these findings tell us with regard to the physiological role of AT1 receptors in the VLM in the tonic and phasic regulation of sympathetic vasomotor activity and blood pressure.

  5. Improvement in renal hemodynamics following combined angiotensin II infusion and AT1R blockade in aged female sheep following fetal unilateral nephrectomy.

    Directory of Open Access Journals (Sweden)

    Reetu R Singh

    Full Text Available Renin-angiotensin system (RAS is a powerful modulator of renal hemodynamic and fluid homeostasis. Up-regulation in components of intra-renal RAS occurs with ageing. Recently we reported that 2 year old uninephrectomised (uni-x female sheep have low renin hypertension and reduced renal function. By 5 years of age, these uni-x sheep had augmented decrease in renal blood flow (RBF compared to sham. We hypothesised that this decrease in RBF in 5 year old uni-x sheep was due to an up-regulation in components of the intra-renal RAS. In this study, renal responses to angiotensin II (AngII infusion and AngII type 1 receptor (AT1R blockade were examined in the same 5 year old sheep. We also administered AngII in the presence of losartan to increase AngII bioavailability to the AT2R in order to understand AT2R contribution to renal function in this model. Uni-x animals had significantly lower renal cortical content of renin, AngII (∼40% and Ang 1-7 (∼60% and reduced cortical expression of AT1R gene than sham animals. In response to both AngII infusion and AT1R blockade via losartan, renal hemodynamic responses and tubular sodium excretion were significantly attenuated in uni-x animals compared to sham. However, AngII infusion in the presence of losartan caused ∼33% increase in RBF in uni-x sheep compared to ∼14% in sham (P<0.05. This was associated with a significant decrease in renal vascular resistance in the uni-x animals (22% vs 15%, P<0.05 without any changes in systemic blood pressure. The present study shows that majority of the intra-renal RAS components are suppressed in this model of low renin hypertension. However, increasing the availability of AngII to AT2R by AT1R blockade improved renal blood flow in uni-x sheep. This suggests that manipulation of the AT2R maybe a potential therapeutic target for treatment of renal dysfunction associated with a congenital nephron deficit.

  6. Alpha-receptor blockade improves muscle perfusion and glucose uptake in heart failure.

    NARCIS (Netherlands)

    Gomes, M.E.R.; Mulder, A.; Bellersen, L.; Verheugt, F.W.A.; Smits, P.; Tack, C.J.J.


    AIMS: Alpha-adrenergic receptor-mediated vasoconstriction might underlie the insulin resistance seen in conditions associated with increased sympathetic tone, like chronic heart failure (CHF). Alpha-adrenergic receptor blockade by phentolamine could improve forearm blood flow (FBF) and forearm

  7. Mechanisms of acute neurovascular protection with AT1 blockade after stroke: Effect of prestroke hypertension.

    Directory of Open Access Journals (Sweden)

    Ahmed Alhusban

    Full Text Available Stroke is a leading cause of adult disability worldwide. Improving stroke outcome requires an orchestrated interplay that involves up regulation of pro-survival pathways and a concomitant suppression of pro-apoptotic mediators. In this investigation, we assessed the involvement of eNOS in the AT1 blocker-mediated protective and pro-recovery effects in animals with hypertension. We also evaluated the effect of acute eNOS inhibition in hypertensive animals. To achieve these goals, spontaneously hypertensive rats (SHR were implanted with blood pressure transmitters, and randomized to receive either an eNOS inhibitor (L-NIO or saline one hour before cerebral ischemia induction. After 3 hours of ischemia, animals were further randomized to receive either candesartan or saline at the time of reperfusion and sacrificed either 24 hours or 7 days later. Candesartan induced an early protective effect that was independent of eNOS inhibition (50% improvement in motor function. However, the protective effect of candesartan was associated with about five fold up regulation of BDNF expression and about three fold reduction in ER stress markers, in an eNOS dependent manner. The early benefit of a single dose of candesartan, present at 24 hours after stroke, was diminished at 7 days, perhaps due to a failure to induce an angiogenic response in these hypertensive animals. In conclusion, our findings demonstrate an early prorecovery effect of candesartan at both functional and molecular levels. Candesartan induced prorecovery signaling was mediated through eNOS. This effect was not maintained at 7 days after experimental ischemia.

  8. AT1 Receptor Gene Polymorphisms in relation to Postprandial Lipemia


    Klop, B.; van den Berg, T. M.; Rietveld, A.P.; Chaves, J.; Real, J. T.; Ascaso, J. F.; Carmena, R.; Elte, J W F; Manuel Castro Cabezas


    Background. Recent data suggest that the renin-angiotensin system may be involved in triglyceride (TG) metabolism. We explored the effect of the common A1166C and C573T polymorphisms of the angiotensin II type 1 receptor (AT1R) gene on postprandial lipemia. Methods. Eighty-two subjects measured daytime capillary TG, and postprandial lipemia was estimated as incremental area under the TG curve. The C573T and A1166C polymorphisms of the AT1R gene were determined. Results. Postprandial lipemia w...

  9. Peripheral cannabinoid 1 receptor blockade activates brown adipose tissue and diminishes dyslipidemia and obesity

    NARCIS (Netherlands)

    Boon, M.R.; Kooijman, S.; Dam, A.D. van; Pelgrom, L.R.; Berbée, J.F.P.; Visseren, C.A.R.; Aggele, R.C. van; Hoek, A.M. van den; Sips, H.C.M.; Lombès, M.; Havekes, L.M.; Tamsma, J.T.; Guigas, B.; Meijer, O.C.; Jukema, J.W.; Rensen, P.C.N.


    The endocannabinoid system is an important player in energy metabolism by regulating appetite, lipolysis, and energy expenditure. Chronic blockade of the cannabinoid 1 receptor (CB1R) leads to long-term maintenance of weight loss and reduction of dyslipidemia in experimental and human obesity. The

  10. Systemic blockade of D2-like dopamine receptors facilitates extinction of conditioned fear in mice


    Ponnusamy, Ravikumar; Nissim, Helen A.; Barad, Mark


    Extinction of conditioned fear in animals is the explicit model of behavior therapy for human anxiety disorders, including panic disorder, obsessive-compulsive disorder, and post-traumatic stress disorder. Based on previous data indicating that fear extinction in rats is blocked by quinpirole, an agonist of dopamine D2 receptors, we hypothesized that blockade of D2 receptors might facilitate extinction in mice, while agonists should block extinction, as they do in rats. One day after fear con...

  11. D2 receptor blockade by risperidone correlates with attention deficits in late-life schizophrenia. (United States)

    Uchida, Hiroyuki; Rajji, Tarek K; Mulsant, Benoit H; Kapur, Shitij; Pollock, Bruce G; Graff-Guerrero, Ariel; Menon, Mahesh; Mamo, David C


    The negative impact of antipsychotic drugs on attention is expected to be greater in late-life schizophrenia because of the age-related changes in the dopamine receptor reserve. The objective of this study was to examine the relationship between dopamine D2 receptor blockade by risperidone and the cognitive function in late-life schizophrenia. Subjects with schizophrenia or schizoaffective disorder aged 50 or older who were receiving risperidone completed a [C]raclopride positron emission tomography scan to measure D2-binding potential in the striatum. The D2 receptor blockade by risperidone was calculated using age-corrected measures from healthy individuals and region of interest analysis of dynamic positron emission tomography data coregistered to the subjects' magnetic resonance imaging scans. Cognitive function was assessed using a battery of neuropsychological tests that included the Dementia Rating Scale-2 (DRS). Eleven subjects (mean +/- SD age, 64 +/- 8 years) participated in this study. The mean +/- SD D2 receptor blockade was 69% +/- 14% (range, 34%-80%). The age-corrected score on the attention subscale in the DRS was negatively correlated with the D2 receptor blockade. The DRS attention subscale score was lower in the subjects who experienced 74.9% or higher D2 blockade (median value, corresponding to a daily risperidone dose of >3.0 mg) than in those who did not. Although a causal attribution cannot be made in light of the cross-sectional nature of this study, the results suggest the critical importance of identifying the lowest effective dose of antipsychotic drugs in older patients with schizophrenia.

  12. AT1 Receptor Gene Polymorphisms in relation to Postprandial Lipemia

    Directory of Open Access Journals (Sweden)

    B. Klop


    Full Text Available Background. Recent data suggest that the renin-angiotensin system may be involved in triglyceride (TG metabolism. We explored the effect of the common A1166C and C573T polymorphisms of the angiotensin II type 1 receptor (AT1R gene on postprandial lipemia. Methods. Eighty-two subjects measured daytime capillary TG, and postprandial lipemia was estimated as incremental area under the TG curve. The C573T and A1166C polymorphisms of the AT1R gene were determined. Results. Postprandial lipemia was significantly higher in homozygous carriers of the 1166-C allele (9.39±8.36 mM*h/L compared to homozygous carriers of the 1166-A allele (2.02±6.20 mM*h/L (P<0.05. Postprandial lipemia was similar for the different C573T polymorphisms. Conclusion. The 1166-C allele of the AT1R gene seems to be associated with increased postprandial lipemia. These data confirm the earlier described relationships between the renin-angiotensin axis and triglyceride metabolism.

  13. Orexin-1 receptor blockade dysregulates REM sleep in the presence of orexin-2 receptor antagonism

    Directory of Open Access Journals (Sweden)

    Christine eDugovic


    Full Text Available In accordance with the prominent role of orexins in the maintenance of wakefulness via activation of orexin-1 (OX1R and orexin-2 (OX2R receptors, various dual OX1/2R antagonists have been shown to promote sleep in animals and humans. While selective blockade of OX2R seems to be sufficient to initiate and prolong sleep, the beneficial effect of additional inhibition of OX1R remains controversial. The relative contribution of OX1R and OX2R to the sleep effects induced by a dual OX1/2R antagonist was further investigated in the rat, and specifically on rapid eye movement (REM sleep since a deficiency of the orexin system is associated with narcolepsy/cataplexy based on clinical and pre-clinical data. As expected, the dual OX1/2R antagonist SB-649868 was effective in promoting non-REM (NREM and REM sleep following oral dosing (10 and 30 mg/kg at the onset of the dark phase. However, a disruption of REM sleep was evidenced by a more pronounced reduction in the onset of REM as compared to NREM sleep, a marked enhancement of the REM/total sleep ratio, and the occurrence of a few episodes of direct wake to REM sleep transitions (REM intrusion. When administered subcutaneously, the OX2R antagonist JNJ-10397049 (10 mg/kg increased NREM duration whereas the OX1R antagonist GSK-1059865 (10 mg/kg did not alter sleep. REM sleep was not affected either by OX2R or OX1R blockade alone, but administration of the OX1R antagonist in combination with the OX2R antagonist induced a significant reduction in REM sleep latency and an increase in REM sleep duration at the expense of the time spent in NREM sleep. These results indicate that additional blockade of OX1R to OX2R antagonism elicits a dysregulation of REM sleep by shifting the balance in favor of REM sleep at the expense of NREM sleep that may increase the risk of adverse events. Translation of this hypothesis remains to be tested in the clinic.

  14. Investigation of Prolactin Receptor Activation and Blockade Using Time-Resolved Fluorescence Resonance Energy Transfer

    Directory of Open Access Journals (Sweden)

    Estelle eTallet


    Full Text Available The prolactin receptor (PRLR is emerging as a therapeutic target in oncology. Knowledge-based drug design led to the development of a pure PRLR antagonist (Del1-9-G129R-hPRL that was recently shown to prevent PRL-induced mouse prostate tumorogenesis. In humans, the first gain-of-function mutation of the PRLR (PRLRI146L was recently identified in breast tumor patients. At the molecular level, the actual mechanism of action of these two novel players in the PRL system remains elusive. In this study, we addressed whether constitutive PRLR activation (PRLRI146L or PRLR blockade (antagonist involved alteration of receptor oligomerization and/or of inter-chain distances compared to unstimulated and PRL-stimulated PRLR. Using a combination of various biochemical and spectroscopic approaches (co-IP, blue-native electrophoresis, BRET1, we demonstrated that preformed PRLR homodimers are altered neither by PRL- or I146L-induced receptor triggering, nor by antagonist-mediated blockade. These findings were confirmed using a novel time-resolved fluorescence resonance energy transfer (TR-FRET technology that allows monitoring distance changes between cell-surface tagged receptors. This technology revealed that PRLR blockade or activation did not involve detectable distance changes between extracellular domains of receptor chains within the dimer. This study merges with our previous structural investigations suggesting that the mechanism of PRLR activation solely involves intermolecular contact adaptations leading to subtle intramolecular rearrangements.

  15. Endothelin-A receptor blockade slows the progression of renal injury in experimental renovascular disease. (United States)

    Kelsen, Silvia; Hall, John E; Chade, Alejandro R


    Endothelin (ET)-1, a potent renal vasoconstrictor with mitogenic properties, is upregulated by ischemia and has been shown to induce renal injury via the ET-A receptor. The potential role of ET-A blockade in chronic renovascular disease (RVD) has not, to our knowledge, been previously reported. We hypothesized that chronic ET-A receptor blockade would preserve renal hemodynamics and slow the progression of injury of the stenotic kidney in experimental RVD. Renal artery stenosis, a major cause of chronic RVD, was induced in 14 pigs and observed for 6 wk. In half of the pigs, chronic ET-A blockade was initiated (RVD+ET-A, 0.75 mg·kg(-1)·day(-1)) at the onset of RVD. Single-kidney renal blood flow, glomerular filtration rate, and perfusion were quantified in vivo after 6 wk using multidetector computer tomography. Renal microvascular density was quantified ex vivo using three-dimensional microcomputer tomography, and growth factors, inflammation, apoptosis, and fibrosis were determined in renal tissue. The degree of stenosis and increase in blood pressure were similar in RVD and RVD+ET-A pigs. Renal hemodynamics, function, and microvascular density were decreased in the stenotic kidney but preserved by ET-A blockade, accompanied by increased renal expression of vascular endothelial growth factor, hepatocyte growth factor, and downstream mediators such as phosphorilated-Akt, angiopoietins, and endothelial nitric oxide synthase. ET-A blockade also reduced renal apoptosis, inflammation, and glomerulosclerosis. This study shows that ET-A blockade slows the progression of renal injury in experimental RVD and preserves renal hemodynamics, function, and microvascular density in the stenotic kidney. These results support a role for ET-1/ET-A as a potential therapeutic target in chronic RVD.

  16. Binding of Losartan to Angiotensin AT1 Receptors Increases Dopamine D1 Receptor Activation (United States)

    Li, Dong; Scott, Lena; Crambert, Susanne; Zelenin, Sergey; Eklöf, Ann-Christine; Di Ciano, Luis; Ibarra, Fernando


    Signaling through both angiotensin AT1 receptors (AT1R) and dopamine D1 receptors (D1R) modulates renal sodium excretion and arterial BP. AT1R and D1R form heterodimers, but whether treatment with AT1R antagonists functionally modifies D1R via allosterism is unknown. In this study, the AT1R antagonist losartan strengthened the interaction between AT1R and D1R and increased expression of D1R on the plasma membrane in vitro. In rat proximal tubule cells that express endogenous AT1R and D1R, losartan increased cAMP generation. Losartan increased cAMP in HEK 293a cells transfected with both AT1R and D1R, but it did not increase cAMP in cells transfected with either receptor alone, suggesting that losartan induces D1R activation. Furthermore, losartan did not increase cAMP in HEK 293a cells expressing AT1R and mutant S397/S398A D1R, which disrupts the physical interaction between AT1R and D1R. In vivo, administration of a D1R antagonist significantly attenuated the antihypertensive effect of losartan in rats with renal hypertension. Taken together, these data imply that losartan might exert its antihypertensive effect both by inhibiting AT1R signaling and by enhancing D1R signaling. PMID:22193384

  17. Blockade of NMDA receptors prevents analgesic tolerance to repeated transcutaneous electrical nerve stimulation (TENS) in rats (United States)

    Hingne, Priyanka M.; Sluka, Kathleen A.


    Repeated daily application transcutaneous electrical nerve stimulation (TENS) results in tolerance, at spinal opioid receptors, to the anti-hyperalgesia produced by TENS. Since N-Methyl-D-Aspartate (NMDA) receptor antagonists prevent analgesic tolerance to opioid agonists we hypothesized that blockade of NMDA receptors will prevent tolerance to TENS. In rats with knee joint inflammation, TENS was applied for 20 minute daily at high frequency (100 Hz), low frequency (4 Hz), or sham TENS. Rats were treated with the NMDA antagonist MK-801 (0.01 mg/kg-0.1 mg/kg) or vehicle daily before TENS. Paw withdrawal thresholds were tested before and after inflammation, and before and after TENS treatment for 4 days. On day 1 TENS reversed the decreased mechanical withdrawal threshold induced by joint inflammation. On day 4 TENS had no effect on the decreased withdrawal threshold in the group treated with vehicle demonstrating development of tolerance. However, in the group treated with 0.1 mg/kg MK-801, TENS significantly reversed the mechanical withdrawal thresholds on day 4 demonstrating that tolerance did not develop. Vehicle treated animals developed cross-tolerance at spinal opioid receptors. Treatment with MK-801 reversed this cross-tolerance at spinal opioid receptors. In summary, blockade of NMDA receptors prevents analgesic tolerance to daily TENS by preventing tolerance at spinal opioid receptors. Perspective Tolerance observed to the clinical treatment of TENS could be prevented by administration of pharmaceutical agents with NMDA receptors activity such as ketamine or dextromethorphan. PMID:18061543

  18. Peripheral cannabinoid 1 receptor blockade activates brown adipose tissue and diminishes dyslipidemia and obesity. (United States)

    Boon, Mariëtte R; Kooijman, Sander; van Dam, Andrea D; Pelgrom, Leonard R; Berbée, Jimmy F P; Visseren, Cheryl A R; van Aggele, Robin C; van den Hoek, Anita M; Sips, Hetty C M; Lombès, Marc; Havekes, Louis M; Tamsma, Jouke T; Guigas, Bruno; Meijer, Onno C; Jukema, J Wouter; Rensen, Patrick C N


    The endocannabinoid system is an important player in energy metabolism by regulating appetite, lipolysis, and energy expenditure. Chronic blockade of the cannabinoid 1 receptor (CB1R) leads to long-term maintenance of weight loss and reduction of dyslipidemia in experimental and human obesity. The molecular mechanism by which CB1R blockade reverses dyslipidemia in obesity has not yet been clarified. In this study, we showed that CB1R blockade with the systemic CB1R blocker rimonabant enhanced whole-body energy expenditure and activated brown adipose tissue (BAT), indicated by increased expression of genes involved in BAT thermogenesis and decreased lipid droplet size in BAT. This was accompanied by selectively increased triglyceride (TG) uptake by BAT and lower plasma TG levels. Interestingly, the effects on BAT activation were still present at thermoneutrality and could be recapitulated by using the strictly peripheral CB1R antagonist AM6545, indicating direct peripheral activation of BAT. Indeed, CB1R blockade directly activated T37i brown adipocytes, resulting in enhanced uncoupled respiration, most likely via enhancing cAMP/PKA signaling via the adrenergic receptor pathway. Our data indicate that selective targeting of the peripheral CB1R in BAT has therapeutic potential in attenuating dyslipidemia and obesity. © FASEB.

  19. Fear memory in a neurodevelopmental model of schizophrenia based on the postnatal blockade of NMDA receptors. (United States)

    Latusz, Joachim; Radaszkiewicz, Aleksandra; Bator, Ewelina; Wędzony, Krzysztof; Maćkowiak, Marzena


    Epidemiological data have indicated that memory impairment is observed during adolescence in groups at high risk for schizophrenia and might precede the appearance of schizophrenia symptoms in adulthood. In the present study, we used a neurodevelopmental model of schizophrenia based on the postnatal blockade of N-methyl-d-aspartate (NMDA) receptors in rats to investigate fear memory in adolescence and adulthood. The rats were treated with increasing doses of CGP 37849 (CGP), a competitive antagonist of the NMDA receptor (1.25mg/kg on days 1, 3, 6, 9; 2.5mg/kg on days 12, 15, 18 and 5mg/kg on day 21). Fear memory was analysed in delay and trace fear conditioning. Sensorimotor gating deficit, which is another cognitive symptom of schizophrenia, was also determined in adolescent and adult CGP-treated rats. Postnatal CGP administration disrupted cue- and context-dependent fear memory in adolescent rats in both delay and trace conditioning. In contrast, CGP administration evoked impairment only in cue-dependent fear memory in rats exposed to trace but not delay fear conditioning. The postnatal blockade of NMDA receptors induced sensorimotor gating deficits in adult rats but not in adolescent rats. The postnatal blockade of NMDA receptors induced fear memory impairment in adolescent rats before the onset of neurobehavioral deficits associated with schizophrenia. Copyright © 2016. Published by Elsevier Urban & Partner Sp. z o.o.

  20. Endothelin B receptor blockade attenuates pulmonary vasodilation in oxygen-ventilated fetal lambs. (United States)

    Ivy, D Dunbar; Lee, Dong-Seok; Rairigh, Robyn L; Parker, Thomas A; Abman, Steven H


    Endothelin-1 (ET-1) contributes to the regulation of pulmonary vascular tone in the normal ovine fetus and in models of perinatal pulmonary hypertension. In the fetal lamb lung, the effects of ET-1 depend on the balance of at least two endothelin receptor subtypes: ETA and ETB. ETA receptors are located on smooth muscle cells and mediate vasoconstriction and smooth muscle proliferation. Stimulation of endothelial ETB receptors causes vasodilation through release of nitric oxide and also functions to remove ET-1 from the circulation. However, whether activation of ETB receptors contributes to the fall in pulmonary vascular tone at birth is unknown. To determine the role of acute ETB receptor blockade in pulmonary vasodilation in response to birth-related stimuli, we studied the hemodynamic effects of selective ETB receptor blockade with BQ-788 during mechanical ventilation with low (<10%) and high FiO2 (100%) in near-term fetal sheep. Intrapulmonary infusion of BQ-788 did not change left pulmonary artery (LPA) blood flow and pulmonary vascular resistance (PVR) at baseline. In comparison with controls, BQ-788 treatment attenuated the rise in LPA flow with low and high FiO2 ventilation (p <0.001 vs. control for each FiO2 concentration). PVR progressively decreased during mechanical ventilation with low and high FiO2 in both groups, but PVR remained higher after BQ-788 treatment throughout the study period (p <0.001). We conclude that selective ETB receptor blockade attenuates pulmonary vasodilation at birth. We speculate that ETB receptor stimulation contributes to pulmonary vasodilation at birth in the ovine fetus.

  1. Angiotensin II AT1 receptors mediate neuronal sensitization and sustained blood pressure response induced by a single injection of amphetamine. (United States)

    Marchese, N A; Paz, M C; Caeiro, X; Dadam, F M; Baiardi, G; Perez, M F; Bregonzio, C


    A single exposure to amphetamine induces neurochemical sensitization in striatal areas. The neuropeptide angiotensin II, through AT1 receptors (AT1-R) activation, is involved in these responses. However, amphetamine-induced alterations can be extended to extra-striatal areas involved in blood pressure control and their physiological outcomes. Our aim for the present study was to analyze the possible role for AT1-R in these events using a two-injection protocol and to further characterize the proposed AT1-R antagonism protocol. Central effect of orally administered AT1-R blocker (Candesartan, 3mg/kg p.o.×5days) in male Wistar rats was analyzed by spontaneous activity of neurons within locus coeruleus. In another group of animals pretreated with the AT1-R blocker or vehicle, sensitization was achieved by a single administration of amphetamine (5mg/kg i.p. - day 6) followed by a 3-week period off drug. On day 27, after receiving an amphetamine challenge (0.5mg/kg i.p.), we evaluated: (1) the sensitized c-Fos expression in locus coeruleus (LC), nucleus of the solitary tract (NTS), caudal ventrolateral medulla (A1) and central amygdala (CeAmy); and (2) the blood pressure response. AT1-R blockade decreased LC neurons' spontaneous firing rate. Moreover, sensitized c-Fos immunoreactivity in TH+neurons was found in LC and NTS; and both responses were blunted by the AT1-R blocker pretreatment. Meanwhile, no differences were found neither in CeAmy nor A1. Sensitized blood pressure response was observed as sustained changes in mean arterial pressure and was effectively prevented by AT1-R blockade. Our results extend AT1-R role in amphetamine-induced sensitization over noradrenergic nuclei and their cardiovascular output. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

  2. Activation of the sympathetic nervous system mediates hypophagic and anxiety-like effects of CB₁ receptor blockade. (United States)

    Bellocchio, Luigi; Soria-Gómez, Edgar; Quarta, Carmelo; Metna-Laurent, Mathilde; Cardinal, Pierre; Binder, Elke; Cannich, Astrid; Delamarre, Anna; Häring, Martin; Martín-Fontecha, Mar; Vega, David; Leste-Lasserre, Thierry; Bartsch, Dusan; Monory, Krisztina; Lutz, Beat; Chaouloff, Francis; Pagotto, Uberto; Guzman, Manuel; Cota, Daniela; Marsicano, Giovanni


    Complex interactions between periphery and the brain regulate food intake in mammals. Cannabinoid type-1 (CB1) receptor antagonists are potent hypophagic agents, but the sites where this acute action is exerted and the underlying mechanisms are not fully elucidated. To dissect the mechanisms underlying the hypophagic effect of CB1 receptor blockade, we combined the acute injection of the CB1 receptor antagonist rimonabant with the use of conditional CB1-knockout mice, as well as with pharmacological modulation of different central and peripheral circuits. Fasting/refeeding experiments revealed that CB1 receptor signaling in many specific brain neurons is dispensable for the acute hypophagic effects of rimonabant. CB1 receptor antagonist-induced hypophagia was fully abolished by peripheral blockade of β-adrenergic transmission, suggesting that this effect is mediated by increased activity of the sympathetic nervous system. Consistently, we found that rimonabant increases gastrointestinal metabolism via increased peripheral β-adrenergic receptor signaling in peripheral organs, including the gastrointestinal tract. Blockade of both visceral afferents and glutamatergic transmission in the nucleus tractus solitarii abolished rimonabant-induced hypophagia. Importantly, these mechanisms were specifically triggered by lipid-deprivation, revealing a nutrient-specific component acutely regulated by CB1 receptor blockade. Finally, peripheral blockade of sympathetic neurotransmission also blunted central effects of CB1 receptor blockade, such as fear responses and anxiety-like behaviors. These data demonstrate that, independently of their site of origin, important effects of CB1 receptor blockade are expressed via activation of peripheral sympathetic activity. Thus, CB1 receptors modulate bidirectional circuits between the periphery and the brain to regulate feeding and other behaviors.

  3. Characterization of 18F-FPyKYNE-Losartan for Imaging AT1 Receptors. (United States)

    Hachem, Maryam; Tiberi, Mario; Ismail, Basma; Hunter, Chad R; Arksey, Natasha; Hadizad, Tayebeh; Beanlands, Rob S; deKemp, Robert A; DaSilva, Jean N


    Most physiologic effects of the renin angiotensin system (RAS) are mediated via the angiotensin (Ang) type 1 receptor (AT1R). The 18F-FPyKYNE derivative of the clinically used AT1R blocker losartan exhibits high binding selectivity for kidney AT1R and rapid metabolism in rats. The aim of this study was to further assess the binding profile of this novel PET agent for imaging AT1R in rats and pigs. In vitro binding assays were performed with 18F-FPyKYNE-losartan in rat kidneys. Male Sprague-Dawley rats were used to assess dosimetry, antagonistic efficacy via blood pressure measurements, and presence of labeled metabolites in kidneys. Test-retest PET imaging, blocking with AT1R antagonist candesartan (10 mg/kg), and plasma metabolism analysis were performed in female Yorkshire pigs. 18F-FPyKYNE-losartan bound with high affinity (dissociation constant of 49.4 ± 18.0 nM and maximal binding of 348 ± 112 fmol/mm2) to rat kidney AT1R. It bound strongly to plasma proteins in rats (97%), and its labeled metabolites displayed minimal interference on renal AT1R binding. FPyKYNE-losartan fully antagonized the Ang II pressor effect, albeit with 4-fold potency reduction (the effective dose inhibiting 50% of the Ang II-induced maximal pressor response of 25.5 mg/kg) relative to losartan. PET imaging exhibited high kidney-to-blood contrast and slow renal clearance, with an SUV of 14.1 ± 6.2. Excellent reproducibility was observed in the calculated test-retest variability (7.2% ± 0.75%). Only hydrophilic-labeled metabolites were present in plasma samples, and renal retention was reduced (-60%) at 10-15 min after blockade with candesartan. 18F-FPyKYNE-losartan has a favorable binding profile and displays high potential for translational work in humans as an AT1R PET imaging agent. © 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

  4. Oxytocin receptor blockade: a new principle in the treatment of preterm labor?

    DEFF Research Database (Denmark)

    Andersen, L F; Lyndrup, J; Akerlund, M


    The concentration of myometrial and decidual oxytocin receptors increases dramatically in normal women in late pregnancy, causing enhanced uterine sensitivity to physiologic levels of oxytocin. Similar increase in myometrial oxytocin receptors has been found in women in preterm labor, indicating...... a role for oxytocin also in idiopathic preterm labor. A newly synthesized oxytocin analogue, 1-deamino-2-D-Tyr-(OEt)-4-Thr-8-Orn-oxytocin, has been found to be a competitive inhibitor of oxytocin. The present study was conducted to test its efficacy in suppressing uterine contractions during preterm...... of the patients. These preliminary findings support the concept that an increased concentration of uterine oxytocin receptors is an important etiologic factor in uncomplicated preterm labor and therefore oxytocin receptor blockade may be a therapeutic alternative for this condition....

  5. Dopamine D2-receptor blockade enhances decoding of prefrontal signals in humans. (United States)

    Kahnt, Thorsten; Weber, Susanna C; Haker, Helene; Robbins, Trevor W; Tobler, Philippe N


    The prefrontal cortex houses representations critical for ongoing and future behavior expressed in the form of patterns of neural activity. Dopamine has long been suggested to play a key role in the integrity of such representations, with D2-receptor activation rendering them flexible but weak. However, it is currently unknown whether and how D2-receptor activation affects prefrontal representations in humans. In the current study, we use dopamine receptor-specific pharmacology and multivoxel pattern-based functional magnetic resonance imaging to test the hypothesis that blocking D2-receptor activation enhances prefrontal representations. Human subjects performed a simple reward prediction task after double-blind and placebo controlled administration of the D2-receptor antagonist amisulpride. Using a whole-brain searchlight decoding approach we show that D2-receptor blockade enhances decoding of reward signals in the medial orbitofrontal cortex. Examination of activity patterns suggests that amisulpride increases the separation of activity patterns related to reward versus no reward. Moreover, consistent with the cortical distribution of D2 receptors, post hoc analyses showed enhanced decoding of motor signals in motor cortex, but not of visual signals in visual cortex. These results suggest that D2-receptor blockade enhances content-specific representations in frontal cortex, presumably by a dopamine-mediated increase in pattern separation. These findings are in line with a dual-state model of prefrontal dopamine, and provide new insights into the potential mechanism of action of dopaminergic drugs. Copyright © 2015 the authors 0270-6474/15/354104-08$15.00/0.

  6. Age dependence of the rapid antidepressant and synaptic effects of acute NMDA receptor blockade

    Directory of Open Access Journals (Sweden)

    Elena eNosyreva


    Full Text Available Ketamine is a NMDA receptor antagonist that produces rapid antidepressant responses in individuals with major depressive disorder. The antidepressant action of ketamine has been linked to blocking NMDA receptor activation at rest, which inhibits eukaryotic elongation factor2 kinase leading to desuppression of protein synthesis and synaptic potentiation in the CA1 region of the hippocampus. Here, we investigated ketamine mediated antidepressant response and the resulting synaptic potentiation in juvenile animals. We found that ketamine did not produce an antidepressant response in juvenile animals in the novelty suppressed feeding or the forced swim test. In addition ketamine application failed to trigger synaptic potentiation in hippocampal slices obtained from juvenile animals, unlike its action in slices from older animals (6-9 weeks old. The inability of ketamine to trigger an antidepressant response or subsequent synaptic plasticity processes suggests a developmental component to ketamine mediated antidepressant efficacy. We also show that the NMDAR antagonist AP5 triggers synaptic potentiation in mature hippocampus similar to the action of ketamine, demonstrating that global competitive blockade of NMDA receptors is sufficient to trigger this effect. These findings suggest that global blockade of NMDA receptors in developmentally mature hippocampal synapses are required for the antidepressant efficacy of ketamine.

  7. Combined blockade of angiotensin II and prorenin receptors ameliorates podocytic apoptosis induced by IgA-activated mesangial cells. (United States)

    Leung, Joseph C K; Chan, Loretta Y Y; Saleem, M A; Mathieson, P W; Tang, Sydney C W; Lai, Kar Neng


    Glomerulo-podocytic communication plays an important role in the podocytic injury in IgA nephropathy (IgAN). In this study, we examine the role of podocytic angiotensin II receptor subtype 1 (AT1R) and prorenin receptor (PRR) in podocytic apoptosis in IgAN. Polymeric IgA (pIgA) was isolated from patients with IgAN and healthy controls. Conditioned media were prepared from growth arrested human mesangial cells (HMC) incubated with pIgA from patients with IgAN (IgA-HMC media) or healthy controls (Ctl-HMC media). A human podocyte cell line was used as a model to examine the regulation of the expression of AT1R, PRR, TNF-α and CTGF by IgA-HMC media. Podocytic nephrin expression, annexin V binding and caspase 3 activity were used as the functional readout of podocytic apoptosis. IgA-HMC media had no effect on AngII release by podocytes. IgA-HMC media significantly up-regulated the expression of AT1R and PRR, down-regulated nephrin expression and induced apoptosis in podocytes. Mono-blockade of AT1R, PRR, TNF-α or CTGF partially reduced podocytic apoptosis. IgA-HMC media activated NFκB, notch1 and HEY1 expression by podocytes and dual blockade of AT1R with PRR, or anti-TNF-α with anti-CTGF, effectively rescued the podocytic apoptosis induced by IgA-HMC media. Our data suggests that pIgA-activated HMC up-regulates the expression of AT1R and PRR expression by podocytes and the associated activation of NFκB and notch signalling pathways play an essential role in the podocytic apoptosis induced by glomerulo-podocytic communication in IgAN. Simultaneously targeting the AT1R and PRR could be a potential therapeutic option to reduce the podocytic injury in IgAN.

  8. Renoprotective effects of angiotensin II receptor blockade in type 1 diabetic patients with diabetic nephropathy

    DEFF Research Database (Denmark)

    Andersen, S; Tarnow, L; Rossing, P


    and hemodynamic effects of specific intervention in the renin-angiotensin system by blockade of the angiotensin II subtype-1 receptor to the effect of ACE inhibition. METHODS: A randomized, double-blind, cross-over trial was performed in 16 type 1 diabetic patients (10 men), age 42 +/- 2 years (mean +/- SEM...... inhibition is primarily caused by interference in the renin-angiotensin system. Our study suggest that losartan represents a valuable new drug in the treatment of hypertension and proteinuria in type 1 diabetic patients with diabetic nephropathy....

  9. Is interleukin-6 receptor blockade the Holy Grail for inflammatory diseases?

    DEFF Research Database (Denmark)

    Febbraio, M A; Rose-John, S; Pedersen, B K


    Interleukin-6 (IL-6) has been linked to a myriad of diseases associated with inflammation, including rheumatoid arthritis (RA), Crohn's disease, and several types of cancer. In 2009 the US Food and Drug Administration accepted a complete-response submission for the use of Actemra (tocilizumab), t......), the first humanized IL-6 receptor-inhibiting monoclonal antibody, for the treatment of RA. Although this treatment will certainly help in managing inflammatory disorders such as RA, we suggest that side effects of such blockade may be excess weight gain and hyperlipidemia....

  10. Insulin induces upregulation of vascular AT1 receptor gene expression by posttranscriptional mechanisms. (United States)

    Nickenig, G; Röling, J; Strehlow, K; Schnabel, P; Böhm, M


    An interaction of insulin with angiotensin II effects could be pathophysiologically important for the pathogenesis of atherosclerosis and hypertension. We examined the effect of insulin on AT1 receptor gene expression in cultured vascular smooth muscle cells (VSMCs). A 24-hour incubation with insulin (100 nmol/L) produced a 2-fold increase in AT1 receptor density on VSMCs, as assessed by radioligand binding assays. This enhanced AT1 receptor expression was caused by a time- and concentration-dependent upregulation of the AT1 receptor mRNA levels, as assessed by Northern analysis. The maximal effect was detected after a 24-hour incubation of cells with 100 nmol/L insulin (270+/-20%). AT1 receptor upregulation was caused by a stabilization of the AT1 receptor mRNA, because the AT1 receptor mRNA half-life was prolonged from 5 hours under basal conditions to 10 hours after insulin stimulation. In contrast, insulin had no influence on AT1 receptor gene transcription, as assessed by nuclear run-on assays. The insulin-induced AT1 receptor upregulation was followed by an increased functional response, because angiotensin II evoked a significantly elevated intracellular release of calcium in cells that were preincubated with 100 nmol/L insulin for 24 hours. The insulin-induced AT1 receptor upregulation was dependent on tyrosine kinases, as assessed by experiments with the tyrosine kinase inhibitor genistein. Furthermore, experiments using the intracellular calcium chelator bis(2-amino-5-methylphenoxy)ethane-N, N,N',N'-tetraacetic acid tetraacetoxymethyl ester suggest that intracellular calcium release may be involved in AT1 receptor regulation. Insulin-induced upregulation of the AT1 receptor by posttranscriptional mechanisms may explain the association of hyperinsulinemia with hypertension and arteriosclerosis, because activation of the AT1 receptor plays a key role in the regulation of blood pressure and fluid homeostasis.

  11. Adenosine A2B receptor blockade slows growth of bladder and breast tumors. (United States)

    Cekic, Caglar; Sag, Duygu; Li, Yuesheng; Theodorescu, Dan; Strieter, Robert M; Linden, Joel


    The accumulation of high levels of adenosine in tumors activates A(2A) and A(2B) receptors on immune cells and inhibits their ability to suppress tumor growth. Deletion of adenosine A(2A) receptors (A(2A)ARs) has been reported to activate antitumor T cells, stimulate dendritic cell (DC) function, and inhibit angiogenesis. In this study, we evaluated the effects of intermittent intratumor injection of a nonselective adenosine receptor antagonist, aminophylline (AMO; theophylline ethylenediamine) and, for the first time to our knowledge, a selective A(2B)AR antagonist, ATL801. AMO and ATL801 slowed the growth of MB49 bladder and 4T1 breast tumors in syngeneic mice and reduced by 85% metastasizes of breast cancer cells from mammary fat to lung. Based on experiments with A(2A)AR(-/-) or adenosine A(2B) receptor(-/-) mice, the effect of AMO injection was unexpectedly attributed to A(2B)AR and not to A(2A)AR blockade. AMO and ATL801 significantly increased tumor levels of IFN-γ and the IFN-inducible chemokine CXCL10, which is a ligand for CXCR3. This was associated with an increase in activated tumor-infiltrating CXCR3(+) T cells and a decrease in endothelial cell precursors within tumors. Tumor growth inhibition by AMO or ATL801 was eliminated in CXCR3(-/-) mice and RAG1(-/-) mice that lack mature T cells. In RAG1(-/-) mice, A(2B)AR deletion enhanced CD86 expression on CD11b(-) DCs. Bone marrow chimera experiments demonstrated that CXCR3 and A(2B)AR expression on bone marrow cells is required for the antitumor effects of AMO. The data suggest that blockade of A(2B)ARs enhances DC activation and CXCR3-dependent antitumor responses.

  12. Dual Mechanism of Interleukin-3 Receptor Blockade by an Anti-Cancer Antibody

    Directory of Open Access Journals (Sweden)

    Sophie E. Broughton


    Full Text Available Interleukin-3 (IL-3 is an activated T cell product that bridges innate and adaptive immunity and contributes to several immunopathologies. Here, we report the crystal structure of the IL-3 receptor α chain (IL3Rα in complex with the anti-leukemia antibody CSL362 that reveals the N-terminal domain (NTD, a domain also present in the granulocyte-macrophage colony-stimulating factor (GM-CSF, IL-5, and IL-13 receptors, adopting unique “open” and classical “closed” conformations. Although extensive mutational analyses of the NTD epitope of CSL362 show minor overlap with the IL-3 binding site, CSL362 only inhibits IL-3 binding to the closed conformation, indicating alternative mechanisms for blocking IL-3 signaling. Significantly, whereas “open-like” IL3Rα mutants can simultaneously bind IL-3 and CSL362, CSL362 still prevents the assembly of a higher-order IL-3 receptor-signaling complex. The discovery of open forms of cytokine receptors provides the framework for development of potent antibodies that can achieve a “double hit” cytokine receptor blockade.

  13. Repeated blockade of mineralocorticoid receptors, but not of glucocorticoid receptors impairs food rewarded spatial learning

    NARCIS (Netherlands)

    Douma, B. R.; Korte, S. M.; Buwalda, B.; La Fleur, S. E.; Bohus, B.; Luiten, P. G.


    Corticosteroids from the adrenal cortex influence a variety of behaviours including cognition, learning and memory. These hormones act via two intracellular receptors, the mineralo-corticoid receptor (MR) and the glucocorticoid receptor (GR). These two receptor types display a high concentration and

  14. Repeated blockade of mineralocorticoid receptors, but not of glucocorticoid receptors impairs food rewarded spatial learning

    NARCIS (Netherlands)

    Douma, BRK; Korte, SM; Buwalda, B; la Fleur, SE; Bohus, B; Luiten, PGM

    Corticosteroids from the adrenal cortex influence a variety of behaviours including cognition, learning and memory. These hormones act via two intracellular receptors, the mineralo-corticoid receptor (MR) and the glucocorticoid receptor (GR). These two receptor types display a high concentration and

  15. 5HT2A receptor blockade in dorsomedial striatum reduces repetitive behaviors in BTBR mice. (United States)

    Amodeo, D A; Rivera, E; Cook, E H; Sweeney, J A; Ragozzino, M E


    Restricted and repetitive behaviors are a defining feature of autism, which can be expressed as a cognitive flexibility deficit or stereotyped, motor behaviors. There is limited knowledge about the underlying neuropathophysiology contributing to these behaviors. Previous findings suggest that central 5HT2A receptor activity is altered in autism, while recent work indicates that systemic 5HT2A receptor antagonist treatment reduces repetitive behaviors in an idiopathic model of autism. 5HT2A receptors are expressed in the orbitofrontal cortex and striatum. These two regions have been shown to be altered in autism. The present study investigated whether 5HT2A receptor blockade in the dorsomedial striatum or orbitofrontal cortex in the BTBR mouse strain, an idiopathic model of autism, affects the phenotype related to restricted and repetitive behaviors. Microinfusion of the 5HT2A receptor antagonist, M100907 into the dorsomedial striatum alleviated a reversal learning impairment and attenuated grooming behavior. M100907 infusion into the orbitofrontal cortex increased perseveration during reversal learning and potentiated grooming. These findings suggest that increased 5HT2A receptor activity in the dorsomedial striatum may contribute to behavioral inflexibility and stereotyped behaviors in the BTBR mouse. 5HT2A receptor signaling in the orbitofrontal cortex may be critical for inhibiting a previously learned response during reversal learning and expression of stereotyped behavior. The present results suggest which brain areas exhibit abnormalities underlying repetitive behaviors in an idiopathic mouse model of autism, as well as which brain areas systemic treatment with M100907 may principally act on in BTBR mice to attenuate repetitive behaviors. © 2016 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

  16. Mechanism for blockade of angiotensin subtype 1 receptors to lower plasma glucose in streptozotocin-induced diabetic rats. (United States)

    Chan, P; Liu, I-M; Tzeng, T-F; Yang, T-L; Cheng, J-T


    reduction of elevated mRNA or protein level of hepatic PEPCK. Both of these effects were blocked by opioid micro-receptor antagonist. The results suggest that blockade of AT(1) receptor by valsartan may enhance the adrenal beta-endorphin secretion induced by ACh, activating the opioid micro-receptors to increase glucose utilization and/or to decrease hepatic gluconeogenesis, resulting in the reduction of plasma glucose in STZ-induced diabetic rats.

  17. Blockade of alcohol's amnestic activity in humans by an alpha5 subtype benzodiazepine receptor inverse agonist. (United States)

    Nutt, David J; Besson, Marie; Wilson, Susan J; Dawson, Gerard R; Lingford-Hughes, Anne R


    Alcohol produces many subjective and objective effects in man including pleasure, sedation, anxiolysis, plus impaired eye movements and memory. In human volunteers we have used a newly available GABA-A/benzodiazepine receptor inverse agonist that is selective for the alpha5 subtype (a5IA) to evaluate the role of this subtype in mediating these effects of alcohol on the brain. After pre-treatment with a5IA, we found almost complete blockade of the marked impairment caused by alcohol (mean breath concentration 150mg/100ml) of word list learning and partial but non-significant reversal of subjective sedation without effects on other measures such as intoxication, liking, and slowing of eye movements. This action was not due to alterations in alcohol kinetics and so provides the first proof of concept that selectively decreasing GABA-A receptor function at a specific receptor subtype can offset some actions of alcohol in humans. It also supports growing evidence for a key role of the alpha5 subtype in memory. Inverse agonists at other GABA-A receptor subtypes may prove able to reverse other actions of alcohol, and so offer a new approach to understanding the actions of alcohol in the human brain and in the treatment of alcohol related disorders in humans.

  18. Effects of Mineralocorticoid Receptors Blockade on FearMemory Reconsolidation in Rats

    Directory of Open Access Journals (Sweden)

    Ali Rashidy-Pour


    Full Text Available Reconsolidation memory is defined as a process in which the retrieval of a previously consolidated memory returns to a labile state which is then subject to stabilization. Previous studies have shown that mineralocorticoid receptors (MRs modulate distinct phases of learning and memory, which display a high concentration and distinct distribution in the hippocampus. Moreover, we found no studies that examined the role of hippocampal MRs in fear memory reconsolidation. Here, we investigated the effect of MRs blockade on fear memory reconsolidation in rats. Additionally, to test whether blockade of protein synthesis would disrupt fear memory reconsolidation in our paradigm, we tested the effect of cycloheximide, an inhibitor of protein synthesis after memory reactivation. Results indicated that systemic as well as intra-hippocampal administrations of the MR antagonist spironolactone immediately following memory reactivation did not affect on post-retrieval long-term memory. Cycloheximide given after the reactivation treatment produced a strong impairment that persisted over test sessions. These findings indicate that MRs are not required for reconsolidation of fear-based memory.

  19. Alpha 2-adrenergic receptor turnover in adipose tissue and kidney: irreversible blockade of alpha 2-adrenergic receptors by benextramine

    Energy Technology Data Exchange (ETDEWEB)

    Taouis, M.; Berlan, M.; Lafontan, M.


    The recovery of post- and extrasynaptic alpha 2-adrenergic receptor-binding sites was studied in vivo in male golden hamsters after treatment with an irreversible alpha-adrenoceptor antagonist benextramine, a tetramine disulfide that possesses a high affinity for alpha 2-binding sites. The kidney alpha 2-adrenergic receptor number was measured with (/sup 3/H)yohimbine, whereas (/sup 3/H)clonidine was used for fat cell and brain membrane alpha 2-binding site identification. Benextramine treatment of fat cell, kidney, and brain membranes reduced or completely suppressed, in an irreversible manner, (/sup 3/H) clonidine and (/sup 3/H)yohimbine binding without modifying adenosine (A1-receptor) and beta-adrenergic receptor sites. This irreversible binding was also found 1 and 2 hr after intraperitoneal administration of benextramine to the hamsters. Although it bound irreversibly to peripheral and central alpha 2-adrenergic receptors on isolated membranes, benextramine was unable to cross the blood-brain barrier of the hamster at the concentrations used (10-20 mg/kg). After the irreversible blockade, alpha 2-binding sites reappeared in kidney and adipose tissue following a monoexponential time course. Recovery of binding sites was more rapid in kidney than in adipose tissue; the half-lives of the receptor were 31 and 46 hr, respectively in the tissues. The rates of receptor production were 1.5 and 1.8 fmol/mg of protein/hr in kidney and adipose tissue. Reappearance of alpha 2-binding sites was associated with a rapid recovery of function (antilipolytic potencies of alpha 2-agonists) in fat cells inasmuch as occupancy of 15% of (/sup 3/H)clonidine-binding sites was sufficient to promote 40% inhibition of lipolysis. Benextramine is a useful tool to estimate turnover of alpha 2-adrenergic receptors under normal and pathological situations.

  20. Colony-stimulating factor 1 receptor blockade prevents fractionated whole-brain irradiation-induced memory deficits. (United States)

    Feng, Xi; Jopson, Timothy D; Paladini, Maria Serena; Liu, Sharon; West, Brian L; Gupta, Nalin; Rosi, Susanna


    Primary central nervous system (CNS) neoplasms and brain metastases are routinely treated with whole-brain radiation. Long-term survival occurs in many patients, but their quality of life is severely affected by the development of cognitive deficits, and there is no treatment to prevent these adverse effects. Neuroinflammation, associated with activation of brain-resident microglia and infiltrating monocytes, plays a pivotal role in loss of neurological function and has been shown to be associated with acute and long-term effects of brain irradiation. Colony-stimulating factor 1 receptor (CSF-1R) signaling is essential for the survival and differentiation of microglia and monocytes. Here, we tested the effects of CSF-1R blockade by PLX5622 on cognitive function in mice treated with three fractions of 3.3 Gy whole-brain irradiation. Young adult C57BL/6J mice were given three fractions of 3.3 Gy whole-brain irradiation while they were on diet supplemented with PLX5622, and the effects on periphery monocyte accumulation, microglia numbers, and neuronal functions were assessed. The mice developed hippocampal-dependent cognitive deficits at 1 and 3 months after they received fractionated whole-brain irradiation. The impaired cognitive function correlated with increased number of periphery monocyte accumulation in the CNS and decreased dendritic spine density in hippocampal granule neurons. PLX5622 treatment caused temporary reduction of microglia numbers, inhibited monocyte accumulation in the brain, and prevented radiation-induced cognitive deficits. Blockade of CSF-1R by PLX5622 prevents fractionated whole-brain irradiation-induced memory deficits. Therapeutic targeting of CSF-1R may provide a new avenue for protection from radiation-induced memory deficits.

  1. Relevance of dorsal raphe nucleus firing in serotonin 5-HT2C receptor blockade-induced augmentation of SSRIs effects

    NARCIS (Netherlands)

    Sotty, Florence; Folgering, Joost H. A.; Brennum, Lise T.; Hogg, Sandra; Mork, Arne; Hertel, Peter; Cremers, Thomas I. F. H.

    Selective serotonin reuptake inhibitors are the most widely prescribed antidepressant drugs. However, they exhibit a slow onset of action, putatively due to the initial decrease in serotonin cell firing mediated via somato-dendritic autoreceptors. Interestingly, blockade of 5-HT2C receptors

  2. Normotensive sodium loading in normal man: Regulation of renin secretion during beta-receptor blockade

    DEFF Research Database (Denmark)

    Mølstrøm, Simon; Larsen, Nils Heden; Simonsen, Jane Angel


    Saline administration may change renin system (RAAS) activity and sodium excretion at constant mean arterial pressure (MAP). We hypothesized that such responses are elicited mainly by renal sympathetic nerve activity by beta1-receptors (beta1-RSNA), and tested the hypothesis by studying RAAS...... and renal excretion during slow saline loading at constant plasma sodium con-centration (Na-loading: 12 micromol Na(+) kg(-1) min(-1) for 4 h). Normal subjects were studied on low-sodium intake with and without beta1-adrenergic blockade by metoprolol. Metoprolol per se reduced RAAS activity as expected. Na......-loading decreased plasma renin (PRC) by 1/3, AngII by 1/2, and aldosterone (pAldo) by 2/3, (all p

  3. Mineralocorticoid receptor blockade prevents stress-induced modulation of multiple memory systems in the human brain. (United States)

    Schwabe, Lars; Tegenthoff, Martin; Höffken, Oliver; Wolf, Oliver T


    Accumulating evidence suggests that stress may orchestrate the engagement of multiple memory systems in the brain. In particular, stress is thought to favor dorsal striatum-dependent procedural over hippocampus-dependent declarative memory. However, the neuroendocrine mechanisms underlying these modulatory effects of stress remain elusive, especially in humans. Here, we targeted the role of the mineralocorticoid receptor (MR) in the stress-induced modulation of dorsal striatal and hippocampal memory systems in the human brain using a combination of event-related functional magnetic resonance imaging and pharmacologic blockade of the MR. Eighty healthy participants received the MR antagonist spironolactone (300 mg) or a placebo and underwent a stressor or control manipulation before they performed, in the scanner, a classification task that can be supported by the hippocampus and the dorsal striatum. Stress after placebo did not affect learning performance but reduced explicit task knowledge and led to a relative increase in the use of more procedural learning strategies. At the neural level, stress promoted striatum-based learning at the expense of hippocampus-based learning. Functional connectivity analyses showed that this shift was associated with altered coupling of the amygdala with the hippocampus and dorsal striatum. Mineralocorticoid receptor blockade before stress prevented the stress-induced shift toward dorsal striatal procedural learning, same as the stress-induced alterations of amygdala connectivity with hippocampus and dorsal striatum, but resulted in significantly impaired performance. Our findings indicate that the stress-induced shift from hippocampal to dorsal striatal memory systems is mediated by the amygdala, required to preserve performance after stress, and dependent on the MR. © 2013 Society of Biological Psychiatry.

  4. Adenosine A2B receptor blockade slows growth of bladder and breast tumors1 (United States)

    Cekic, Caglar; Sag, Duygu; Li, Yuesheng; Theodorescu, Dan; Strieter, Robert M.; Linden, Joel


    The accumulation of high levels of adenosine in tumors activates A2A and A2B receptors on immune cells and inhibits their ability to suppress tumor growth. Deletion of A2AARs has been reported to activate anti-tumor T cells, stimulates DC function and inhibits angiogenesis. Here we evaluated the effects of intermittent intratumor injection of a non-selective adenosine receptor antagonist, aminophylline (AMO, theophylline ethylenediamine) and, for the first time, a selective A2BAR antagonist, ATL801. AMO and ATL801 slowed the growth of MB49 bladder and 4T1 breast tumors in syngeneic mice, and reduced by 85% metastasizes of breast cancer cells from mammary fat to lung. Based on experiments with A2AAR−/− or A2BAR−/− mice, the effect of AMO injection was unexpectedly attributed to A2BAR and not to A2AAR blockade. AMO and ATL801 significantly increased tumor levels of IFNγ and the interferon-inducible chemokine CXCL10, which is a ligand for CXCR3. This was associated with an increase in activated tumor-infiltrating CXCR3+ T cells and a decrease in endothelial cell precursors within tumors. Tumor growth inhibition by AMO or ATL801 was eliminated in CXCR3−/− mice and in RAG1−/− mice that lack mature T cells. In RAG1−/− mice A2BAR deletion enhanced CD86 expression on CD11b- DCs. Bone marrow chimera experiments demonstrated that CXCR3 and A2BAR expression on bone marrow cells are required for the anti-tumor effects of AMO. The data suggest that blockade of A2BARs enhances DC activation and CXCR3-dependent anti-tumor responses. PMID:22116822

  5. Muscle-type nicotinic receptor blockade by diethylamine, the hydrophilic moiety of lidocaine

    Directory of Open Access Journals (Sweden)

    Armando eAlberola-Die


    Full Text Available Lidocaine bears in its structure both an aromatic ring and a terminal amine, which can be protonated at physiological pH, linked by an amide group. Since lidocaine causes multiple inhibitory actions on nicotinic acetylcholine receptors (nAChRs, this work was aimed to determine the inhibitory effects of diethylamine (DEA, a small molecule resembling the hydrophilic moiety of lidocaine, on Torpedo marmorata nAChRs microtransplanted to Xenopus oocytes. Similarly to lidocaine, DEA reversibly blocked acetylcholine-elicited currents (IACh in a dose-dependent manner (IC50 close to 70 μM, but unlike lidocaine, DEA did not affect IACh desensitization. IACh inhibition by DEA was more pronounced at negative potentials, suggesting an open-channel blockade of nAChRs, although roughly 30% inhibition persisted at positive potentials, indicating additional binding sites outside the pore. DEA block of nAChRs in the resting state (closed channel was confirmed by the enhanced IACh inhibition when pre-applying DEA before its co-application with ACh, as compared with solely DEA and ACh co-application. Virtual docking assays provide a plausible explanation to the experimental observations in terms of the involvement of different sets of drug binding sites. So, at the nAChR transmembrane (TM domain, DEA and lidocaine shared binding sites within the channel pore, giving support to their open-channel blockade; besides, lidocaine, but not DEA, interacted with residues at cavities among the M1, M2, M3 and M4 segments of each subunit and also at intersubunit crevices. At the extracellular (EC domain, DEA and lidocaine binding sites were broadly distributed, which aids to explain the closed channel blockade observed. Interestingly, some DEA clusters were located at the α-γ interphase of the EC domain, in a cavity near the orthosteric binding site pocket; by contrast, lidocaine contacted with all α-subunit loops conforming the ACh binding site, both in α-γ and

  6. Blockade of orexin-1 receptors attenuates orexin-2 receptor antagonism-induced sleep promotion in the rat. (United States)

    Dugovic, Christine; Shelton, Jonathan E; Aluisio, Leah E; Fraser, Ian C; Jiang, Xiaohui; Sutton, Steven W; Bonaventure, Pascal; Yun, Sujin; Li, Xiaorong; Lord, Brian; Dvorak, Curt A; Carruthers, Nicholas I; Lovenberg, Timothy W


    Orexins are peptides produced by lateral hypothalamic neurons that exert a prominent role in the maintenance of wakefulness by activating orexin-1 (OX1R) and orexin-2 (OX2R) receptor located in wake-active structures. Pharmacological blockade of both receptors by the dual OX1/2R antagonist (2R)-2-[(1S)-6,7-dimethoxy-1-{2-[4-(trifluoromethyl)phenyl]ethyl}-3,4-dihydroisoquinolin-2(1H)-yl]-N-methyl-2-phenylethanamide (almorexant) has been shown to promote sleep in animals and humans during their active period. However, the selective distribution of OX1R and OX2R in distinct neuronal circuits may result in a differential impact of these receptors in sleep-wake modulation. The respective role of OX1R and OX2R on sleep in correlation with monoamine release was evaluated in rats treated with selective antagonists alone or in combination. When administered in either phase of the light/dark cycle, the OX2R antagonist 1-(2,4-dibromophenyl)-3-[(4S,5S)-2,2-dimethyl-4-phenyl-1,3-dioxan-5-yl]urea (JNJ-10397049) decreased the latency for persistent sleep and increased nonrapid eye movement and rapid eye movement sleep time. Almorexant produced less hypnotic activity, whereas the OX1R antagonist 1-(6,8-difluoro-2-methylquinolin-4-yl)-3-[4-(dimethylamino)phenyl]urea (SB-408124) had no effect. Microdialysis studies showed that either OX2R or OX1/2R antagonism decreased extracellular histamine concentration in the lateral hypothalamus, whereas both OX1R and OX1/2R antagonists increased dopamine release in the prefrontal cortex. Finally, coadministration of the OX1R with the OX2R antagonist greatly attenuated the sleep-promoting effects of the OX2R antagonist. These results indicate that blockade of OX2R is sufficient to initiate and prolong sleep, consistent with the hypothesis of a deactivation of the histaminergic system. In addition, it is suggested that simultaneous inhibition of OX1R attenuates the sleep-promoting effects mediated by selective OX2R blockade, possibly correlated

  7. Abilities of candesartan and other AT1 receptor blockers to impair angiotensin II-induced AT1 receptor activation after wash-out (United States)

    Kiya, Yoshihiro; Miura, Shin-ichiro; Matsuo, Yoshino; Karnik, Sadashiva S; Saku, Keijiro


    Angiotensin II (Ang II) binds to Ang II type 1 (AT1) receptor and evokes cell signaling, and subsequently stimulates vasoconstriction and cell proliferation, which eventually lead to cardiovascular disease. Since most AT1 receptor blockers (ARBs) have molecular (differential) effects, we evaluated the specific features of candesartan and compared the abilities of candesartan and other ARBs (olmesartan, telmisartan, valsartan, irbesartan and losartan) to bind to and activate AT1 receptors using a cell-based wash-out assay. Each ARB blocked Ang II-induced extracellular signal-regulated kinase (ERK) activation and inositol phosphate production to different degrees after wash-out. In addition, a small difference in the molecular structure, i.e. a carboxyl group, between candesartan and candesartan-7H was associated with a difference in the degree of this blocking effect. In addition, interaction between Gln257 in the AT1 receptor and the carboxyl group of candesartan may be partially associated with the effect of candesartan after wash-out. Although our findings regarding the molecular effects of ARB are based on basic research, these findings may lead to an exciting new area in the clinical application of ARBs. PMID:21824992

  8. Abilities of candesartan and other AT(1) receptor blockers to impair angiotensin II-induced AT(1) receptor activation after wash-out. (United States)

    Kiya, Yoshihiro; Miura, Shin-ichiro; Matsuo, Yoshino; Karnik, Sadashiva S; Saku, Keijiro


    Angiotensin II (Ang II) binds to Ang II type 1 (AT(1)) receptor and evokes cell signaling, and subsequently stimulates vasoconstriction and cell proliferation, which eventually lead to cardiovascular disease. Since most AT(1) receptor blockers (ARBs) have molecular (differential) effects, we evaluated the specific features of candesartan and compared the abilities of candesartan and other ARBs (olmesartan, telmisartan, valsartan, irbesartan and losartan) to bind to and activate AT(1) receptors using a cell-based wash-out assay. Each ARB blocked Ang II-induced extracellular signal-regulated kinase (ERK) activation and inositol phosphate production to different degrees after wash-out. In addition, a small difference in the molecular structure, i.e. a carboxyl group, between candesartan and candesartan-7H was associated with a difference in the degree of this blocking effect. In addition, interaction between Gln(257) in the AT(1) receptor and the carboxyl group of candesartan may be partially associated with the effect of candesartan after wash-out. Although our findings regarding the molecular effects of ARB are based on basic research, these findings may lead to an exciting new area in the clinical application of ARBs.

  9. Immunohistochemical Localization of AT1a, AT1b, and AT2 Angiotensin II Receptor Subtypes in the Rat Adrenal, Pituitary, and Brain with a Perspective Commentary

    Directory of Open Access Journals (Sweden)

    Courtney Premer


    Full Text Available Angiotensin II increases blood pressure and stimulates thirst and sodium appetite in the brain. It also stimulates secretion of aldosterone from the adrenal zona glomerulosa and epinephrine from the adrenal medulla. The rat has 3 subtypes of angiotensin II receptors: AT1a, AT1b, and AT2. mRNAs for all three subtypes occur in the adrenal and brain. To immunohistochemically differentiate these receptor subtypes, rabbits were immunized with C-terminal fragments of these subtypes to generate receptor subtype-specific antibodies. Immunofluorescence revealed AT1a and AT2 receptors in adrenal zona glomerulosa and medulla. AT1b immunofluorescence was present in the zona glomerulosa, but not the medulla. Ultrastructural immunogold labeling for the AT1a receptor in glomerulosa and medullary cells localized it to plasma membrane, endocytic vesicles, multivesicular bodies, and the nucleus. AT1b and AT2, but not AT1a, immunofluorescence was observed in the anterior pituitary. Stellate cells were AT1b positive while ovoid cells were AT2 positive. In the brain, neurons were AT1a, AT1b, and AT2 positive, but glia was only AT1b positive. Highest levels of AT1a, AT1b, and AT2 receptor immunofluorescence were in the subfornical organ, median eminence, area postrema, paraventricular nucleus, and solitary tract nucleus. These studies complement those employing different techniques to characterize Ang II receptors.

  10. Immunohistochemical Localization of AT1a, AT1b, and AT2 Angiotensin II Receptor Subtypes in the Rat Adrenal, Pituitary, and Brain with a Perspective Commentary (United States)

    Premer, Courtney; Lamondin, Courtney; Mitzey, Ann; Speth, Robert C.; Brownfield, Mark S.


    Angiotensin II increases blood pressure and stimulates thirst and sodium appetite in the brain. It also stimulates secretion of aldosterone from the adrenal zona glomerulosa and epinephrine from the adrenal medulla. The rat has 3 subtypes of angiotensin II receptors: AT1a, AT1b, and AT2. mRNAs for all three subtypes occur in the adrenal and brain. To immunohistochemically differentiate these receptor subtypes, rabbits were immunized with C-terminal fragments of these subtypes to generate receptor subtype-specific antibodies. Immunofluorescence revealed AT1a and AT2 receptors in adrenal zona glomerulosa and medulla. AT1b immunofluorescence was present in the zona glomerulosa, but not the medulla. Ultrastructural immunogold labeling for the AT1a receptor in glomerulosa and medullary cells localized it to plasma membrane, endocytic vesicles, multivesicular bodies, and the nucleus. AT1b and AT2, but not AT1a, immunofluorescence was observed in the anterior pituitary. Stellate cells were AT1b positive while ovoid cells were AT2 positive. In the brain, neurons were AT1a, AT1b, and AT2 positive, but glia was only AT1b positive. Highest levels of AT1a, AT1b, and AT2 receptor immunofluorescence were in the subfornical organ, median eminence, area postrema, paraventricular nucleus, and solitary tract nucleus. These studies complement those employing different techniques to characterize Ang II receptors. PMID:23573410

  11. Role of Anterior Cingulate Cortex in Instrumental Learning: Blockade of Dopamine D1 Receptors Suppresses Overt but Not Covert Learning. (United States)

    Aly-Mahmoud, Mayada; Carlier, Pascal; Salam, Sherine A; Houari Selmani, Mariam; Moftah, Marie Z; Esclapez, Monique; Boussaoud, Driss


    HIGHLIGHTS Blockade of dopamine D1 receptors in ACC suppressed instrumental learning when overt responding was required.Covert learning through observation was not impaired.After treatment with a dopamine antagonist, instrumental learning recovered but not the rat's pretreatment level of effort tolerance.ACC dopamine is not necessary for acquisition of task-relevant cues during learning, but regulates energy expenditure and effort based decision. Dopamine activity in anterior cingulate cortex (ACC) is essential for various aspects of instrumental behavior, including learning and effort based decision making. To dissociate learning from physical effort, we studied both observational (covert) learning, and trial-and-error (overt) learning. If ACC dopamine activity is required for task acquisition, its blockade should impair both overt and covert learning. If dopamine is not required for task acquisition, but solely for regulating the willingness to expend effort for reward, i.e., effort tolerance, blockade should impair overt learning but spare covert learning. Rats learned to push a lever for food rewards either with or without prior observation of an expert conspecific performing the same task. Before daily testing sessions, the rats received bilateral ACC microinfusions of SCH23390, a dopamine D1 receptor antagonist, or saline-control infusions. We found that dopamine blockade suppressed overt responding selectively, leaving covert task acquisition through observational learning intact. In subsequent testing sessions without dopamine blockade, rats recovered their overt-learning capacity but not their pre-treatment level of effort tolerance. These results suggest that ACC dopamine is not required for the acquisition of conditioned behaviors and that apparent learning impairments could instead reflect a reduced level of willingness to expend effort due to cortical dopamine blockade.

  12. Co-receptor and co-stimulation blockade for mixed chimerism and tolerance without myelosuppressive conditioning

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    Fairchild Paul J


    Full Text Available Abstract Background A major challenge in the application of marrow transplantation as a route to immunological tolerance of a transplanted organ is to achieve hematopoietic stem cell (HSC engraftment with minimal myelosuppressive treatments. Results We here describe a combined antibody protocol which can achieve long-term engraftment with clinically relevant doses of MHC-mismatched bone marrow, without the need for myelosuppressive drugs. Although not universally applicable in all strains, we achieved reliable engraftment in permissive strains with a two-stage strategy: involving first, treatment with anti-CD8 and anti-CD4 in advance of transplantation; and second, treatment with antibodies targeting CD4, CD8 and CD40L (CD154 at the time of marrow transplantation. Long-term mixed chimerism through co-receptor and co-stimulation blockade facilitated tolerance to donor-type skin grafts, without any evidence of donor-antigen driven regulatory T cells. Conclusion We conclude that antibodies targeting co-receptor and co-stimulatory molecules synergise to enable mixed hematopoietic chimerism and central tolerance, showing that neither cytoreductive conditioning nor 'megadoses' of donor bone marrow are required for donor HSC to engraft in permissive strains.

  13. Blockade of cannabinoid 1 receptor improves GLP-1R mediated insulin secretion in mice. (United States)

    González-Mariscal, Isabel; Krzysik-Walker, Susan M; Kim, Wook; Rouse, Michael; Egan, Josephine M


    The cannabinoid 1 receptor (CB1) is an important regulator of energy metabolism. Reports of in vivo and in vitro studies give conflicting results regarding its role in insulin secretion, possibly due to circulatory factors, such as incretins. We hypothesized that this receptor may be a regulator of the entero-insular axis. We found that despite lower food consumption and lower body weight postprandial GLP-1 plasma concentrations were increased in CB1(-/-) mice compared to CB1(+/+) mice administered a standard diet or high fat/sugar diet. Upon exogenous GLP-1 treatment, CB1(-/-) mice had increased glucose-stimulated insulin secretion. In mouse insulinoma cells, cannabinoids reduced GLP-1R-mediated intracellular cAMP accumulation and subsequent insulin secretion. Importantly, such effects were also evident in human islets, and were prevented by pharmacologic blockade of CB1. Collectively, these findings suggest a novel mechanism in which endocannabinoids are negative modulators of incretin-mediated insulin secretion. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  14. Intrarenal Mas and AT1 receptors play a role in mediating the excretory actions of renal interstitial angiotensin-(1-7) infusion in anaesthetized rats. (United States)

    O'Neill, Julie; Healy, Vincent; Johns, Edward J


    What is the central question of this study? Dietary sodium manipulation alters the magnitude of angiotensin-(1-7) [Ang-(1-7)]-induced natriuresis. The present study sought to determine whether this was related to relative changes in the activity of intrarenal Mas and/or AT1 receptors. What is the main finding and its importance? Angiotensin-(1-7)-induced diuresis and natriuresis is mediated by intrarenal Mas receptors. However, intrarenal AT1 receptor blockade also had an inhibitory effect on Ang-(1-7)-induced natriuresis and diuresis. Thus, Ang-(1-7)-induced increases in sodium and water excretion are dependent upon functional Mas and AT1 receptors. We investigated whether angiotensin-(1-7) [Ang-(1-7)]-induced renal haemodynamic and excretory actions were solely dependent upon intrarenal Mas receptor activation or required functional angiotensin II type 1 (AT1 ) receptors. The renin-angiotensin system was enhanced in anaesthetized rats by prior manipulation of dietary sodium intake. Angiotensin-(1-7) and AT1 and Mas receptor antagonists were infused into the kidney at the corticomedullary border. Mas receptor expression was measured in the kidney. Mean arterial pressure, urine flow and fractional sodium excretion were 93 ± 4 mmHg, 46.1 ± 15.7 μl min(-1)  kg(-1) and 1.4 ± 0.3%, respectively, in the normal-sodium group and 91 ± 2 mmHg, 19.1 ± 3.3 μl min(-1)  kg(-1) and 0.7 ± 0.2%, respectively, in the low-sodium group. Angiotensin-(1-7) infusion had no effect on mean arterial pressure in rats receiving a normal-sodium diet but decreased it by 4 ± 5% in rats receiving a low-sodium diet (P Mas receptor inhibition after either losartan or A-779, respectively. Thus, AT1 receptor activation, as well as Mas receptor activation, plays an essential role in mediating Ang-(1-7)-induced natriuresis and diuresis. Whether this is because Ang-(1-7) partly antagonizes AT1 receptors or whether Ang-(1-7)-induced natriuresis is mediated through AT1

  15. Participation of 5-HT and AT1 Receptors within the Rostral Ventrolateral Medulla in the Maintenance of Hypertension in the Goldblatt 1 Kidney-1 Clip Model

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    Cássia T. Bergamaschi


    Full Text Available The hypothesis that changes in neurotransmission within the rostral ventrolateral medulla (RVLM are important to maintain the high blood pressure (BP was tested in Goldblatt one kidney-one clip hypertension model (1K-1C. Male Wistar rats were anesthetized (urethane 1.2 g/kg, i.v., and the effects of bilateral microinjections into the RVLM of the following drugs were measured in 1K-1C or control groups: glutamate (0.1 mol/L, 100 nL and its antagonist kynurenic acid (0.02 mol/L, 100 nL, the angiotensin AT1 receptor antagonist candesartan (0.01 mol/L, 100 nL, and the nonselective 5-HT receptor antagonist methiothepin (0.06 mol/L, 100 nL. Experiments in 1K-1C rats were performed 6 weeks after surgery. In anesthetized rats glutamate response was larger in hypertensive than in normotensive rats (H: Δ67±6.5; N: Δ43±3.54 mmHg. In contrast, kynurenic acid microinjection into the RVLM did not cause any change in BP in either group. The blockade of either AT1 or 5-HT receptors within the RVLM decreased BP only in 1K-1C rats. A largest depressor response was caused by 5-HT receptor blockade. The data suggest that 5-HT and AT1 receptors act tonically to drive RVLM in 1K-1C rats, and these actions within RVLM contribute to the pathogenesis of this model of hypertension.

  16. Serotonin2A receptor blockade and clinical effect in first-episode schizophrenia patients treated with quetiapine

    DEFF Research Database (Denmark)

    Rasmussen, Hans; Ebdrup, Bjorn H; Erritzoe, David


    -episode antipsychotic-naïve schizophrenia patients before and after 6 months of quetiapine treatment. Moreover, we investigated possible relationships between clinical efficacy, oral dose, and plasma levels of quetiapine RESULTS: Significant nonlinear relationships were found between serotonin2A receptor occupancy...... whereas no additional serotonin2A receptor associated treatment effect was obtained above a receptor occupancy of 70%. CONCLUSIONS: Taken together, the data point to a therapeutic role of the serotonin2A receptor in the treatment of subgroups of patients with schizophrenia. Specifically, the study...... indicates a serotonin2A receptor associated therapeutic window on positive symptoms in responding patients in the range between 60% and 70% occupancy in antipsychotic-naïve first-episode schizophrenia. We speculate that non-responding patients need higher dopamine D(2) receptor blockade. Future studies...

  17. Effects of dopamine D1 receptor activation and blockade on dopamine and noradrenaline levels in the rat brain. (United States)

    Avila-Luna, Alberto; Verduzco-Mendoza, Antonio; Bueno-Nava, Antonio


    The noradrenergic and dopaminergic systems are associated with the motor system and have anatomical and functional connections that have not yet been studied. The present study aimed to examine the specific role of D1 receptors (D1Rs) on noradrenergic and dopaminergic responses in the rat brain. Male Wistar rats were assigned to eight groups to receive systemic injection of a D1R agonist (SKF-38393) at 0, 1, 5 or 10mg/kg or injection of a D1R antagonist (SCH-23390) at 0, 0.25, 0.5 or 1mg/kg. Dopamine (DA) and noradrenaline (NA) levels were measured using high-performance liquid chromatography. Injection of SKF-38393 alone at 1, 5 and 10mg/kg did not alter DA levels in the midbrain, cerebral cortex or pons, while it significantly increased these levels in the striatum (at 1 and 10mg/kg), hippocampus (at 1mg/kg) and cerebellum (at 1 and 5mg/kg). Administration of SKF-38393 at 1, 5, and 10mg/kg decreased the NA levels in the midbrain, pons, hippocampus (except at 1mg/kg) and cortex (except at 5mg/kg), whereas the opposite effect was observed in the striatum. SCH-23390 decreased the DA levels in the cortex (at 0.25 and 0.5mg/kg) and pons (at 0.5mg/kg). In contrast, 0.25, 0.5 and 1mg/kg SCH-23390 increased the DA levels in the cerebellum, whereas no differences from the control levels were observed for the DA levels in the striatum, midbrain and hippocampus. SCH-23390 at 0.5 and 1mg/kg increased the NA levels in the striatum. In contrast, the midbrain, hippocampus, cortex, pons and cerebellum did not exhibit altered NA levels. Our results demonstrate that the activation of D1Rs modulates the response of the noradrenergic system in nearly all of the investigated brain structures; thus, the blockade of D1Rs attenuates the effects induced by D1R activation. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  18. Combined, but not individual, blockade of ASIC3, P2X, and EP4 receptors attenuates the exercise pressor reflex in rats with freely perfused hindlimb muscles

    National Research Council Canada - National Science Library

    Stone, Audrey J; Copp, Steven W; Kim, Joyce S; Kaufman, Marc P


    .... The findings in humans resembled ours in decerebrate rats that individual blockade of the receptors to lactic acid, PGE2, and ATP had only small effects on the exercise pressor reflex provided...

  19. N-Methyl-d-Aspartate (NMDA Receptor Blockade Prevents Neuronal Death Induced by Zika Virus Infection

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    Vivian V. Costa


    Full Text Available Zika virus (ZIKV infection is a global health emergency that causes significant neurodegeneration. Neurodegenerative processes may be exacerbated by N-methyl-d-aspartate receptor (NMDAR-dependent neuronal excitoxicity. Here, we have exploited the hypothesis that ZIKV-induced neurodegeneration can be rescued by blocking NMDA overstimulation with memantine. Our results show that ZIKV actively replicates in primary neurons and that virus replication is directly associated with massive neuronal cell death. Interestingly, treatment with memantine or other NMDAR blockers, including dizocilpine (MK-801, agmatine sulfate, or ifenprodil, prevents neuronal death without interfering with the ability of ZIKV to replicate in these cells. Moreover, in vivo experiments demonstrate that therapeutic memantine treatment prevents the increase of intraocular pressure (IOP induced by infection and massively reduces neurodegeneration and microgliosis in the brain of infected mice. Our results indicate that the blockade of NMDARs by memantine provides potent neuroprotective effects against ZIKV-induced neuronal damage, suggesting it could be a viable treatment for patients at risk for ZIKV infection-induced neurodegeneration.

  20. Role of Anterior Cingulate Cortex in Instrumental Learning: Blockade of Dopamine D1 Receptors Suppresses Overt but Not Covert Learning

    Directory of Open Access Journals (Sweden)

    Mayada Aly-Mahmoud


    Full Text Available HIGHLIGHTSBlockade of dopamine D1 receptors in ACC suppressed instrumental learning when overt responding was required.Covert learning through observation was not impaired.After treatment with a dopamine antagonist, instrumental learning recovered but not the rat's pretreatment level of effort tolerance.ACC dopamine is not necessary for acquisition of task-relevant cues during learning, but regulates energy expenditure and effort based decision.Dopamine activity in anterior cingulate cortex (ACC is essential for various aspects of instrumental behavior, including learning and effort based decision making. To dissociate learning from physical effort, we studied both observational (covert learning, and trial-and-error (overt learning. If ACC dopamine activity is required for task acquisition, its blockade should impair both overt and covert learning. If dopamine is not required for task acquisition, but solely for regulating the willingness to expend effort for reward, i.e., effort tolerance, blockade should impair overt learning but spare covert learning. Rats learned to push a lever for food rewards either with or without prior observation of an expert conspecific performing the same task. Before daily testing sessions, the rats received bilateral ACC microinfusions of SCH23390, a dopamine D1 receptor antagonist, or saline-control infusions. We found that dopamine blockade suppressed overt responding selectively, leaving covert task acquisition through observational learning intact. In subsequent testing sessions without dopamine blockade, rats recovered their overt-learning capacity but not their pre-treatment level of effort tolerance. These results suggest that ACC dopamine is not required for the acquisition of conditioned behaviors and that apparent learning impairments could instead reflect a reduced level of willingness to expend effort due to cortical dopamine blockade.

  1. Glucagon and plasma catecholamines during beta-receptor blockade in exercising man

    DEFF Research Database (Denmark)

    Galbo, H; Holst, Janett; Christensen, N J


    Seven men ran at 60% of individual maximal oxygen uptake to exhaustion during beta-adrenergic blockade with propranolol (P), during lipolytic blockade with nicotinic acid (N), or without drugs (C). The total work times (83 +/- 9 (P), 122 +/- 8 (N), 166 +/- 10 (C) min, mean and SE) differed signif...

  2. Immunohistochemical detection of angiotensin AT 1 and AT 2 receptors in prostate cancer (United States)

    Pawlikowski, Marek; Minias, Radosław; Zieliński, Krzysztof W.


    Introduction The human prostate gland contains all the compounds of the renin-angiotensin system (RAS), including AT1 and AT2 angiotensin receptors. The role of local RAS in the prostate pathology is recently discussed. The aim of the present study was the evaluation of AT1 and AT2 expressions in human prostate cancers. Material and methods The investigation was performed in 20 paraffin-embedded needle biopsy specimens from routine diagnostic prostate cancer biopsies. The specimens were stained with hematoxylin and eosin and immunostained with anti-AT1 and anti-AT2 antibodies. For visualization of primary antibodies, the streptavidin-biotin-peroxidase technique was applied. The expression of both receptor proteins was evaluated quantitatively using image analysis method. Results The positive immunostaining with both anti- AT1 and anti-AT2 antibodies can be found in stromal as well as epithelial structures. The results of quantitative evaluation showed the positive correlation between AT1 and AT2 expressions in neoplastic epithelium and overexpression of both AT1 and AT2 in neoplastic epithelium of Gleason grade 2, but not in cancerous structures of Gleason grades 3-5. Conclusions The data on AT1 and AT2 receptor expressions may suggest the involvement of RAS in prostate cancerogenesis. Moreover, the persistence of AT1 receptors in prostate cancer speaks in favor of attempts to use of AT1 receptor blockers (i.e. sartanes) and/or AT2 agonists in prostate cancer prophylaxis and/or treatment. PMID:24578905

  3. AT1 Receptor Antagonism Improves Structural, Functional and Biomechanical Properties in Resistance Arteries in a Rodent Chronic Kidney Disease Model. (United States)

    Quek, K J; Ameer, O Z; Phillips, J K


    The renin-angiotensin system, in particular Angiotensin II (AngII), plays a significant role in the pathogenesis of hypertension in chronic kidney disease (CKD). Effects of chronic AT1 receptor antagonism were investigated in a genetic hypertensive rat model of CKD, the Lewis polycystic kidney (LPK) rat. Mixed-sex LPK and Lewis control rats (total n=31) were split between treated (valsartan 60mg/kg/day p.o. from 4-18 weeks) and vehicle groups. Animals were assessed for systolic blood pressure and urine biochemistry, and after euthanasia, blood collected for urea and creatinine analysis, confirming the hypertensive and renal phenotype. Mesenteric resistance vasculature was assessed using pressure myography and histology. Valsartan treatment improved LPK rats vascular structure, increasing internal and external diameter values and reducing wall thickness (untreated vs. treated LPK: 53.19±3.29 vs. 33.93±2.17m) and wall-lumen ratios (untreated vs. treated LPK: 0.52±0.09 vs. 0.16±0.01 (all P<0.0001). Endothelium dysfunction, as measured by maximal response to acetylcholine (Rmax) was normalized with treatment (untreated vs. treated LPK: 69.56±4.34 vs. 103.05±4.13, P<0.05), increasing the relative contributions of nitric oxide and endothelium-derived hyperpolarization to vasorelaxation while down-regulating the prostanoid contribution. Biomechanical properties also improved with treatment, as indicated by an increase in compliance, decrease in intrinsic stiffness, and alterations in the artery wall composition, which included decreases in collagen density and collagen/elastin ratio. Our results highlight the importance of AngII as a driver of resistance vessel structural, functional and biomechanical dysfunction and provide insight as to how AT1 receptor blockade exerts therapeutic efficacy in CKD.

  4. New models of pulmonary hypertension based on VEGF receptor blockade-induced endothelial cell apoptosis (United States)

    Nicolls, Mark R.; Mizuno, Shiro; Taraseviciene-Stewart, Laima; Farkas, Laszlo; Drake, Jennnifer I.; Al Husseini, Aysar; Gomez-Arroyo, Jose G.; Voelkel, Norbert F.; Bogaard, Herman J.


    In spite of treatment, severe angioproliferative pulmonary arterial hypertension (PAH) remains a disease characterized by great morbidity and shortened survival. New treatment strategies for patients with PAH are needed, and after drug development, preclinical studies are best conducted in animal models which present with pulmonary angio-obliterative disease and right heart failure. A rat model of severe pulmonary hypertension and right heart failure, described a decade ago, continues to be investigated and provide insight into the nature of the lung vascular lesions and mechanisms of cardiac adaptation to an altered lung circulation. This rat model is based on the combination of VEGF receptor blockade with Su5416 and chronic hypoxia; use of this pulmonary hypertension induction strategy led to developing the concept of apoptosis-dependent compensatory vascular cell growth. Although, often employed in experimental designs, chronic hypoxia is not necessary for the development of angio-obliterative pulmonary hypertension. Left pneumonectomy combined with Su5416 also results in severe pulmonary hypertension in normoxic conditions. Similarly, the immune insufficiency component of severe PAH can be modeled in athymic rats (lacking T-lymphocytes). In these rats housed under normoxic conditions, treatment with the VEGFR receptor blocker results in angioproliferative pulmonary hypertension; cardiopulmonary disease in these animals can be prevented by immune reconstitution of regulatory T-cells (Tregs). Finally, chronic hypoxia can be replaced with another stimulator of HIF-1α: Ovalbumin (Ova). Immunization of rats with Ova increases lung tissue HIF-1α protein expression, and in Su5416-treated rats causes lethal pulmonary hypertension. Finally, we postulate that these models may also be useful for “reverse translation”; that is, the mechanisms of lung vascular cell death and growth and the modifying influences of immune and bone marrow cells that have been identified

  5. Interleukin-7 receptor blockade suppresses adaptive and innate inflammatory responses in experimental colitis

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    Willis Cynthia R


    Full Text Available Abstract Background Interleukin-7 (IL-7 acts primarily on T cells to promote their differentiation, survival, and homeostasis. Under disease conditions, IL-7 mediates inflammation through several mechanisms and cell types. In humans, IL-7 and its receptor (IL-7R are increased in diseases characterized by inflammation such as atherosclerosis, rheumatoid arthritis, psoriasis, multiple sclerosis, and inflammatory bowel disease. In mice, overexpression of IL-7 results in chronic colitis, and T-cell adoptive transfer studies suggest that memory T cells expressing high amounts of IL-7R drive colitis and are maintained and expanded with IL-7. The studies presented here were undertaken to better understand the contribution of IL-7R in inflammatory bowel disease in which colitis was induced with a bacterial trigger rather than with adoptive transfer. Methods We examined the contribution of IL-7R on inflammation and disease development in two models of experimental colitis: Helicobacter bilis (Hb-induced colitis in immune-sufficient Mdr1a−/− mice and in T- and B-cell-deficient Rag2−/− mice. We used pharmacological blockade of IL-7R to understand the mechanisms involved in IL-7R-mediated inflammatory bowel disease by analyzing immune cell profiles, circulating and colon proteins, and colon gene expression. Results Treatment of mice with an anti-IL-7R antibody was effective in reducing colitis in Hb-infected Mdr1a−/− mice by reducing T-cell numbers as well as T-cell function. Down regulation of the innate immune response was also detected in Hb-infected Mdr1a−/− mice treated with an anti-IL-7R antibody. In Rag2−/− mice where colitis was triggered by Hb-infection, treatment with an anti-IL-7R antibody controlled innate inflammatory responses by reducing macrophage and dendritic cell numbers and their activity. Conclusions Results from our studies showed that inhibition of IL-7R successfully ameliorated inflammation and disease development

  6. Pharmacological significance of the interplay between angiotensin receptors: MAS receptors as putative final mediators of the effects elicited by angiotensin AT1 receptors antagonists. (United States)

    Pernomian, Larissa; Pernomian, Laena; Gomes, Mayara S; da Silva, Carlos H T P


    The interplay between angiotensin AT1 receptors and MAS receptors relies on several inward regulatory mechanisms from renin-angiotensin system (RAS) including the functional crosstalk between angiotensin II and angiotensin-(1-7), the competitive AT1 antagonism exhibited by angiotensin-(1-7), the antagonist feature assigned to AT1/MAS heterodimerization on AT1 signaling and the AT1-mediated downregulation of angiotensin-converting enzyme 2 (ACE2). Recently, such interplay has acquired an important significance to RAS Pharmacology since a few studies have supporting strong evidences that MAS receptors mediate the effects elicited by AT1 antagonists. The present Perspective provides an overview of the regulatory mechanisms involving AT1 and MAS receptors, their significance to RAS Pharmacology and the future directions on the interplay between angiotensin receptors. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Distinctions between non-peptide angiotensin II AT1-receptor antagonists

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    Georges Vauquelin


    Full Text Available A far-reaching understanding of the molecular action mechanism of AT1-receptor antagonists (AIIAs was obtained by using CHO cells expressing transfected human AT 1-receptors. In this model, direct [3H]-antagonist binding and inhibition of agonist-induced responses (inositol phosphate accumulation can be measured under identical experimental conditions. Whereas preincubation with a surmountable AIIA (losartan causes parallel shifts of the angiotensin II (Ang II concentration-response curve, insurmountable antagonists also cause partial (i.e., 30% for irbesartan, 50% for valsartan, 70% for EXP3174, to almost complete (95% for candesartan reductions of the maximal response. The main conclusions are that all investigated antagonists are competitive with respect to Ang II. They bind to a common or overlapping site on the receptor in a mutually exclusive way. Insurmountable inhibition is related to the slow dissociation rate of the antagonist-receptor complex (t 1/2 of 7 minutes for irbesartan, 17 minutes for valsartan, 30 minutes for EXP3174 and 120 minutes for candesartan. Antagonist-bound AT1-receptors can adopt a fast and a slow reversible state. This is responsible for the partial nature of the insurmountable inhibition. The long-lasting effect of candesartan, the active metabolite of candesartan cilexetil, in vascular smooth muscle contraction studies, as well as in in vivo experiments on rat and in clinical studies, is compatible with its slow dissociation from, and continuous recycling between AT1-receptors. This recycling, or `rebinding' takes place because of the very high affinity of candesartan for the AT1-receptor.

  8. Characterization of Angiotensin II Molecular Determinants Involved in AT1 Receptor Functional Selectivity. (United States)

    Domazet, Ivana; Holleran, Brian J; Richard, Alexandra; Vandenberghe, Camille; Lavigne, Pierre; Escher, Emanuel; Leduc, Richard; Guillemette, Gaétan


    The octapeptide angiotensin II (AngII) exerts a variety of cardiovascular effects through the activation of the AngII type 1 receptor (AT1), a G protein-coupled receptor. The AT1 receptor engages and activates several signaling pathways, including heterotrimeric G proteins Gq and G12, as well as the extracellular signal-regulated kinases (ERK) 1/2 pathway. Additionally, following stimulation, βarrestin is recruited to the AT1 receptor, leading to receptor desensitization. It is increasingly recognized that specific ligands selectively bind and favor the activation of some signaling pathways over others, a concept termed ligand bias or functional selectivity. A better understanding of the molecular basis of functional selectivity may lead to the development of better therapeutics with fewer adverse effects. In the present study, we developed assays allowing the measurement of six different signaling modalities of the AT1 receptor. Using a series of AngII peptide analogs that were modified in positions 1, 4, and 8, we sought to better characterize the molecular determinants of AngII that underlie functional selectivity of the AT1 receptor in human embryonic kidney 293 cells. The results reveal that position 1 of AngII does not confer functional selectivity, whereas position 4 confers a bias toward ERK signaling over Gq signaling, and position 8 confers a bias toward βarrestin recruitment over ERK activation and Gq signaling. Interestingly, the analogs modified in position 8 were also partial agonists of the protein kinase C (PKC)-dependent ERK pathway via atypical PKC isoforms PKCζ and PKCι. Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.

  9. VEGF receptor blockade markedly reduces retinal microglia/macrophage infiltration into laser-induced CNV.

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    Hu Huang

    Full Text Available Although blocking VEGF has a positive effect in wet age-related macular degeneration (AMD, the effect of blocking its receptors remains unclear. This was an investigation of the effect of VEGF receptor (VEGFR 1 and/or 2 blockade on retinal microglia/macrophage infiltration in laser-induced choroidal neovascularization (CNV, a model of wet AMD. CNV lesions were isolated by laser capture microdissection at 3, 7, and 14 days after laser and analyzed by RT-PCR and immunofluorescence staining for mRNA and protein expression, respectively. Neutralizing antibodies for VEGFR1 or R2 and the microglia inhibitor minocycline were injected intraperitoneally (IP. Anti-CD11b, CD45 and Iba1 antibodies were used to confirm the cell identity of retinal microglia/macrophage, in the RPE/choroidal flat mounts or retinal cross sections. CD11b(+, CD45(+ or Iba1(+ cells were counted. mRNA of VEGFR1 and its three ligands, PlGF, VEGF-A (VEGF and VEGF-B, were expressed at all stages, but VEGFR2 were detected only in the late stage. PlGF and VEGF proteins were expressed at 3 and 7 days after laser. Anti-VEGFR1 (MF1 delivered IP 3 days after laser inhibited infiltration of leukocyte populations, largely retinal microglia/macrophage to CNV, while anti-VEGFR2 (DC101 had no effect. At 14 days after laser, both MF1 and DC101 antibodies markedly inhibited retinal microglia/macrophage infiltration into CNV. Therefore, VEGFR1 and R2 play differential roles in the pathogenesis of CNV: VEGFR1 plays a dominant role at 3 days after laser; but both receptors play pivotal roles at 14 days after laser. In vivo imaging demonstrated accumulation of GFP-expressing microglia into CNV in both CX3CR1(gfp/gfp and CX3CR1(gfp/+ mice. Minocycline treatment caused a significant increase in lectin(+ cells in the sub-retinal space anterior to CNV and a decrease in dextran-perfused neovessels compared to controls. Targeting the chemoattractant molecules that regulate trafficking of retinal microglia

  10. Heterogeneous Downregulation of Angiotensin II AT1-A and AT1-B Receptors in Arterioles in STZ-Induced Diabetic Rat Kidneys

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    Zsolt Razga


    Full Text Available Introduction. The renin granulation of kidney arterioles is enhanced in diabetes despite the fact that the level of angiotensin II in the diabetic kidney is elevated. Therefore, the number of angiotensin II AT1-A and AT1-B receptors in afferent and efferent arteriole’s renin-positive and renin-negative smooth muscle cells (SMC was estimated. Method. Immunohistochemistry at the electron microscopic level was combined with 3D stereological sampling techniques. Results. In diabetes the enhanced downregulation of AT1-B receptors in the renin-positive than in the renin-negative SMCs in both arterioles was resulted: the significant difference in the number of AT1 (AT1-A + AT1-B receptors between the two types of SMCs in the normal rats was further increased in diabetes and in contrast with the significant difference observed between the afferent and efferent arterioles in the normal animals, there was no such difference in diabetes. Conclusions. The enhanced downregulation of the AT1-B receptors in the renin-negative SMCs in the efferent arterioles demonstrates that the regulation of the glomerular filtration rate by the pre- and postglomerular arterioles is changed in diabetes. The enhanced downregulation of the AT1-B receptors in the renin-positive SMCs in the arterioles may result in an enhanced level of renin granulation in the arterioles.

  11. Cannabinoid CB1 receptor activation, pharmacological blockade, or genetic ablation affects the function of the muscarinic auto- and heteroreceptor. (United States)

    Schulte, Kirsten; Steingrüber, Nina; Jergas, Bernd; Redmer, Agnes; Kurz, Christina Maria; Buchalla, Rainer; Lutz, Beat; Zimmer, Andreas; Schlicker, Eberhard


    Different types of presynaptic inhibitory Gα(i/o) protein-coupled receptors usually do not act independently of each other but rather pre-activation of receptor X impairs the effect mediated via receptor Y. It is, however, unknown whether this interaction extends to the cannabinoid CB(1) receptor on cholinergic neurones and hence we studied whether its activation, pharmacological blockade, or genetic inactivation affects the function of other presynaptic inhibitory receptors. The electrically evoked acetylcholine or noradrenaline release was determined in superfused rodent tissues preincubated with (3)H-choline or (3)H-noradrenaline. The muscarinic M(2) receptor, Gα(i), and Gα(o) proteins were determined in hippocampal synaptosomes by Western blotting. Hippocampal anandamide and 2-arachidonoyl glycerol levels were determined by LC-MS/MS. The inhibitory effect of the muscarinic receptor agonist oxotremorine on acetylcholine release in hippocampal slices was increased by genetic CB(1) receptor ablation (mouse) and the CB(1) antagonist rimonabant (rat but not mouse) and decreased by a cannabinoid receptor agonist (mouse). In mouse tissues, CB(1) receptor ablation also increased the effect of a δ opioid receptor agonist on acetylcholine release in the hippocampus and the effect of oxotremorine on noradrenaline release in the vas deferens. CB(1) receptor ablation, to a very slight extent, increased Gα(o) protein levels without affecting either Gα(i) and M(2) receptor protein or the levels of anandamide and 2-arachidonoyl glycerol in the hippocampus. In conclusion, the CB(1) receptor shows an inhibitory interaction with the muscarinic and δ opioid receptor on cholinergic neurones in the rodent hippocampus and with the muscarinic receptor on noradrenergic neurones in the mouse vas deferens.

  12. Amelioration strategies fail to prevent tobacco smoke effects on neurodifferentiation: Nicotinic receptor blockade, antioxidants, methyl donors. (United States)

    Slotkin, Theodore A; Skavicus, Samantha; Card, Jennifer; Levin, Edward D; Seidler, Frederic J


    Tobacco smoke exposure is associated with neurodevelopmental disorders. We used neuronotypic PC12 cells to evaluate the mechanisms by which tobacco smoke extract (TSE) affects neurodifferentiation. In undifferentiated cells, TSE impaired DNA synthesis and cell numbers to a much greater extent than nicotine alone; TSE also impaired cell viability to a small extent. In differentiating cells, TSE enhanced cell growth at the expense of cell numbers and promoted emergence of the dopaminergic phenotype. Nicotinic receptor blockade with mecamylamine was ineffective in preventing the adverse effects of TSE and actually enhanced the effect of TSE on the dopamine phenotype. A mixture of antioxidants (vitamin C, vitamin E, N-acetyl-l-cysteine) provided partial protection against cell loss but also promoted loss of the cholinergic phenotype in response to TSE. Notably, the antioxidants themselves altered neurodifferentiation, reducing cell numbers and promoting the cholinergic phenotype at the expense of the dopaminergic phenotype, an effect that was most prominent for N-acetyl-l-cysteine. Treatment with methyl donors (vitamin B12, folic acid, choline) had no protectant effect and actually enhanced the cell loss evoked by TSE; they did have a minor, synergistic interaction with antioxidants protecting against TSE effects on growth. Thus, components of tobacco smoke perturb neurodifferentiation through mechanisms that cannot be attributed to the individual effects of nicotine, oxidative stress or interference with one-carbon metabolism. Consequently, attempted amelioration strategies may be partially effective at best, or, as seen here, can actually aggravate injury by interfering with normal developmental signals and/or by sensitizing cells to TSE effects on neurodifferentiation. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  13. Evidence of changes in alpha-1/AT1 receptor function generated by diet-induced obesity. (United States)

    Juarez, Esther; Tufiño, Cecilia; Querejeta, Enrique; Bracho-Valdes, Ismael; Bobadilla-Lugo, Rosa A


    To study whether hypercaloric diet-induced obesity deteriorates vascular contractility of rat aorta through functional changes in α 1 adrenergic and/or AT1 Angiotensin II receptors. Angiotensin II- or phenylephrine-induced contraction was tested on isolated aorta rings with and without endothelium from female Wistar rats fed for 7 weeks with hypercaloric diet or standard diet. Vascular expression of Angiotensin II Receptor type 1 (AT1R), Angiotensin II Receptor type 2 (AT2R), Cyclooxygenase-1 (COX-1), Cyclooxygenase-2 (COX-2), inducible Nitric Oxide Synthase (iNOS) and endothelial Nitric Oxide Synthase (eNOS), as well as blood pressure, glucose, insulin and angiotensin II blood levels were measured. Diet-induced obesity did not significantly change agonist-induced contractions (Emax and pD 2 hypercaloric diet vs standard diet n.s.d.) of both intact (e+) or endothelium free (e-) vessels but significantly decrease both phenylephrine and angiotensin II contraction (Emax p obesity did not change angiotensin II AT1, AT2 receptor proteins expression but reduced COX-1 and NOS2 ( p obesity produces alterations in vascular adrenergic and angiotensin II receptor dynamics that suggest an endothelium-dependent adrenergic/angiotensin II crosstalk. These changes reflect early-stage vascular responses to obesity.

  14. Hemodynamic and biochemical effects of the AT1 receptor antagonist irbesartan in hypertension

    NARCIS (Netherlands)

    P.J.J. Admiraal (Peter Jan Jacobus); J.A.M.J.L. Janssen (Joseph); J.M. Kroodsma; W.A. de Ronde (Willem); F. Boomsma (Frans); J. Sissmann; P.J. Blankestijn (Peter); P.G.H. Mulder (Paul); A.J. Man in 't Veld (Arie); A.H. van den Meiracker (Anton)


    textabstractWe studied the hemodynamic, neurohumoral, and biochemical effects of the novel angiotensin type 1 (AT1) receptor antagonist irbesartan in 86 untreated patients with essential hypertension on a normal sodium diet. According to a double-blind parallel group trial,

  15. AT1 and AT2 Receptors in the Prelimbic Cortex Modulate the Cardiovascular Response Evoked by Acute Exposure to Restraint Stress in Rats. (United States)

    Brasil, Taíz F S; Fassini, Aline; Corrêa, Fernando M


    The prelimbic cortex (PL) is an important structure in the neural pathway integrating stress responses. Brain angiotensin is involved in cardiovascular control and modulation of stress responses. Blockade of angiotensin receptors has been reported to reduce stress responses. Acute restraint stress (ARS) is a stress model, which evokes sustained blood pressure increase, tachycardia, and reduction in tail temperature. We therefore hypothesized that PL locally generated angiotensin and angiotensin receptors modulate stress autonomic responses. To test this hypothesis, we microinjected an angiotensin-converting enzyme (ACE) inhibitor or angiotensin antagonists into the PL, prior to ARS. Male Wistar rats were used; guide cannulas were bilaterally implanted in the PL for microinjection of vehicle or drugs. A polyethylene catheter was introduced into the femoral artery to record cardiovascular parameters. Tail temperature was measured using a thermal camera. ARS was started 10 min after PL treatment with drugs. Pretreatment with ACE inhibitor lisinopril (0.5 nmol/100 nL) reduced the pressor response, but did not affect ARS-evoked tachycardia. At a dose of 1 nmol/100 nL, it reduced both ARS pressor and tachycardic responses. Pretreatment with candesartan, AT1 receptor antagonist reduced ARS-evoked pressor response, but not tachycardia. Pretreatment with PD123177, AT2 receptor antagonist, reduced tachycardia, but did not affect ARS pressor response. No treatment affected ARS fall in tail temperature. Results suggest involvement of PL angiotensin in the mediation of ARS cardiovascular responses, with participation of both AT1 and AT2 receptors. In conclusion, results indicate that PL AT1-receptors modulate the ARS-evoked pressor response, while AT2-receptors modulate the tachycardic component of the autonomic response.

  16. Selective endothelin A-receptor blockade attenuates coronary microvascular dysfunction after coronary stenting in patients with type 2 diabetes

    Directory of Open Access Journals (Sweden)

    Nikolaos Östlund Papadogeorgos


    Full Text Available Nikolaos Östlund Papadogeorgos, Mattias Bengtsson, Majid KalaniKarolinska Institute, Department of Clinical Sciences, Department of Cardiology, Danderyd Hospital, Stockholm, SwedenBackground: Endothelin-1 may be involved in the development of diabetic microangiopathy. We studied the effect of endothelin-1 blockade on myocardial microcirculation during coronary stenting.Patients and methods: Patients with type 2 diabetes and stable coronary artery disease undergoing elective percutaneous coronary intervention (PCI were randomized to bolus dose of 500 mg bosentan (n = 4, a dual endothelin receptor blocker, or intracoronary administration of 0.03 mmol BQ123 (n = 6, a selective endothelin A-receptor blocker, or placebo (n = 5, respectively. Coronary flow reserve (CFR was measured immediately post-PCI. CFR was also measured in five nondiabetic controls post-coronary stenting.Results: Patients in the placebo group had (P < 0.05 lower values of CFR (2.3 ± 1.2 as compared to those who received endothelin blockade (n = 10; 3.1 ± 0.7 and nondiabetic controls (4.9 ± 2.3. Patients who received BQ123 showed significantly higher CFR (3.3 ± 0.5; P < 0.05 as compared to those on placebo. Nondiabetic patients had significantly higher CFR as compared to patients with diabetes (4.9 ± 2.3 and 2.8 ± 1.0, respectively; P < 0.05. Conclusion: Coronary microvascular dysfunction is present during coronary stenting in patients with type 2 diabetes and may be reversed by selective endothelin A-receptor blockade. Targeting endothelin system may be of importance in protecting the myocardium against ischemic events during elective PCI in type 2 diabetic patients.Keywords: coronary flow reserve, diabetes, endothelin-1, coronary artery disease, coronary angioplasty

  17. Effect of serotonin receptor blockade on endocrine and cardiovascular responses to head-up tilt in humans

    DEFF Research Database (Denmark)

    Matzen, S; Secher, N H; Knigge, U


    Effects of blockade of serotonin (5-HT) receptors on the integrated cardiovascular and endocrine adaptations during head-up tilt were investigated in normal men. In control experiments 50 degrees head-up tilt increased heart rate (HR), total peripheral resistance (TPR), plasma renin activity (PRA...... abolished the adrenomedullary response to hypotension without affecting cardiovascular tolerance or the activity of the pituitary-adrenal axis. The results suggest that serotonergic mechanisms may be involved in the integrated cardiovascular and endocrine responses to central blood volume depletion...

  18. Fibroblast growth factor 23 modifies the pharmacological effects of angiotensin receptor blockade in experimental renal fibrosis

    NARCIS (Netherlands)

    de Jong, Maarten A.; Mirkovic, Katarina; Mencke, Rik; Hoenderop, Joost G.; Bindels, Rene J.; Vervloet, Marc G.; Hillebrands, Jan-Luuk; van den Born, Jacob; Navis, Gerjan; de Borst, Martin H.

    Background. Blockade of the renin-angiotensin-aldosterone system (RAAS) retards progression of chronic kidney disease. Yet, in many patients, the renoprotective effect is incomplete. A high circulating level of the phosphaturic hormone fibroblast growth factor 23 is associated with an impaired

  19. Glucose intolerance induced by blockade of central FGF receptors is linked to an acute stress response

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    Jennifer M. Rojas


    Conclusions: The effect of acute inhibition of central FGFR signaling to impair glucose tolerance likely involves a stress response associated with pronounced, but transient, sympathoadrenal activation and an associated reduction of insulin secretion. Whether this effect is a true consequence of FGFR blockade or involves an off-target effect of the FGFR inhibitor requires additional study.

  20. Endogenous angiotensin II suppresses stretch-induced ANP secretion via AT1 receptor pathway. (United States)

    Oh, Young-Bin; Gao, Shan; Shah, Amin; Kim, Jong Hun; Park, Woo Hyun; Kim, Suhn Hee


    Angiotensin II (Ang II) is released by stretch of cardiac myocytes and has paracrine and autocrine effects on cardiac myocytes and fibroblasts. However, the direct effect of Ang II on the secretion of atrial natriuretic peptide (ANP) is unclear. The aim of the present study is to test whether Ang II affects stretch-induced ANP secretion. The isolated perfused beating atria were used from control and two-kidney one-clip hypertensive (2K1C) rats. The volume load was achieved by elevating the height of outflow catheter connected with isolated atria from 5cmH(2)O to 7.5cmH(2)O. Atrial stretch by volume load caused increases in atrial contractility by 60% and in ANP secretion by 100%. Ang II suppressed stretch-induced ANP secretion and tended to increase atrial contractility whereas losartan stimulated stretch-induced ANP secretion. Neither PD123319 nor A779 had direct effect on stretch-induced ANP secretion. The suppressive effect of Ang II on stretch-induced ANP secretion was blocked by the pretreatment of losartan but not by the pretreatment of PD123319 or A779. In hypertrophied atria from 2K1C rats, stretch-induced ANP concentration attenuated and atrial contractility augmented. The response of stretch-induced ANP secretion to Ang II and losartan augmented. The expression of AT1 receptor protein and mRNA increased but AT2 and Mas receptor mRNA did not change in 2K1C rat atria. Therefore, we suggest that Ang II generated endogenously by atrial stretch suppresses stretch-induced ANP secretion through the AT1 receptor and alteration of Ang II effect in 2K1C rat may be due to upregulation of AT1 receptor. Copyright © 2010 Elsevier Inc. All rights reserved.

  1. The angiotensin II-AT1 receptor stimulates reactive oxygen species within the cell nucleus

    Energy Technology Data Exchange (ETDEWEB)

    Pendergrass, Karl D.; Gwathmey, TanYa M. [The Hypertension and Vascular Research Center, Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157 (United States); Michalek, Ryan D.; Grayson, Jason M. [Department of Microbiology and Immunology, Wake Forest University School of Medicine, Winston-Salem, NC 27157 (United States); Chappell, Mark C., E-mail: [The Hypertension and Vascular Research Center, Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157 (United States)


    We and others have reported significant expression of the Ang II Type 1 receptor (AT1R) on renal nuclei; thus, the present study assessed the functional pathways and distribution of the intracellular AT1R on isolated nuclei. Ang II (1 nM) stimulated DCF fluorescence, an intranuclear indicator of reactive oxygen species (ROS), while the AT1R antagonist losartan or the NADPH oxidase (NOX) inhibitor DPI abolished the increase in ROS. Dual labeling of nuclei with antibodies against nucleoporin 62 (Nup62) and AT1R or the NADPH oxidase isoform NOX4 revealed complete overlap of the Nup62 and AT1R (99%) by flow cytometry, while NOX4 was present on 65% of nuclei. Treatment of nuclei with a PKC agonist increased ROS while the PKC inhibitor GF109203X or PI3 kinase inhibitor LY294002 abolished Ang II stimulation of ROS. We conclude that the Ang II-AT1R-PKC axis may directly influence nuclear function within the kidney through a redox sensitive pathway.

  2. Effect of angiotensin II receptor blockade on proximal tubular fluid reabsorption

    DEFF Research Database (Denmark)

    Leyssac, P P; Karlsen, F M; Holstein-Rathlou, N H


    convolution of halothane-anesthetized Sprague-Dawley rats. Four parameters that depend on the rate of proximal fluid reabsorption were measured: proximal intratubular pressure (Pprox), early and late proximal flow rate, and early distal NaCl concentration. Pprox decreased by 0.5 +/- 0.1 mmHg, late proximal...... flow rate decreased by 2.0 +/- 0.8 nl/min, and early distal NaCl concentration decreased by 4.3 +/- 0.8 mM (mean +/- SE). No changes were observed after microperfusion with saline. Because the tubuloglomerular feedback mechanism was operating in the closed-loop mode, the decreased NaCl load...... the early and late proximal convolutions was estimated to be 7.8 nl/min (approximately 36%). It is concluded that a decrease in local luminal angiotensin II levels and/or AT1 receptor activity under free flow conditions increases the rate of proximal tubular fluid reabsorption....

  3. Combined renin inhibition/(prorenin receptor blockade in diabetic retinopathy--a study in transgenic (mREN227 rats.

    Directory of Open Access Journals (Sweden)

    Wendy W Batenburg

    Full Text Available Dysfunction of renin-angiotensin system (RAS contributes to the pathogenesis of diabetic retinopathy (DR. Prorenin, the precursor of renin is highly elevated in ocular fluid of diabetic patients with proliferative retinopathy. Prorenin may exert local effects in the eye by binding to the so-called (prorenin receptor ((PRR. Here we investigated the combined effects of the renin inhibitor aliskiren and the putative (PRR blocker handle-region peptide (HRP on diabetic retinopathy in streptozotocin (STZ-induced diabetic transgenic (mRen227 rats (a model with high plasma prorenin levels as well as prorenin stimulated cytokine expression in cultured Müller cells. Adult (mRen227 rats were randomly divided into the following groups: (1 non-diabetic; (2 diabetic treated with vehicle; (3 diabetic treated with aliskiren (10 mg/kg per day; and (4 diabetic treated with aliskiren+HRP (1 mg/kg per day. Age-matched non-diabetic wildtype Sprague-Dawley rats were used as control. Drugs were administered by osmotic minipumps for three weeks. Transgenic (mRen227 rat retinas showed increased apoptotic cell death of both inner retinal neurons and photoreceptors, increased loss of capillaries, as well as increased expression of inflammatory cytokines. These pathological changes were further exacerbated by diabetes. Aliskiren treatment of diabetic (mRen227 rats prevented retinal gliosis, and reduced retinal apoptotic cell death, acellular capillaries and the expression of inflammatory cytokines. HRP on top of aliskiren did not provide additional protection. In cultured Müller cells, prorenin significantly increased the expression levels of IL-1α and TNF-α, and this was completely blocked by aliskiren or HRP, their combination, (PRR siRNA and the AT1R blocker losartan, suggesting that these effects entirely depended on Ang II generation by (PRR-bound prorenin. In conclusion, the lack of effect of HRP on top of aliskiren, and the Ang II-dependency of the ocular


    Directory of Open Access Journals (Sweden)

    Lucian Hritcu


    Full Text Available : 3 consecutive days propranolol hydrochloride administration (5 mg/kg b.w., subcutaneous injections under acute and chronic stress conditions causes changes of peripheral erythrocyte distribution in rats. The effects of acute stress and its combination with ȕ-adrenergic receptor blockade on erythrocyte dynamic were more pregnant beside the effects of chronic stress and its combination with ȕ-adrenergic receptor blockade, respectively. ȕ-adrenergic mechanisms were shown to be involved in regulation of erythrocyte dynamic in acute and chronic stress response.

  5. CB1 receptor inhibition leads to decreased vascular AT1 receptor expression, inhibition of oxidative stress and improved endothelial function. (United States)

    Tiyerili, Vedat; Zimmer, Sebastian; Jung, Suzin; Wassmann, Kerstin; Naehle, Claas P; Lütjohann, Dieter; Zimmer, Andreas; Nickenig, Georg; Wassmann, Sven


    Inhibition of the cannabinoid receptor CB(1) (CB(1)-R) exerts numerous positive cardiovascular effects such as modulation of blood pressure, insulin sensitivity and serum lipid concentrations. However, direct vascular effects of CB(1)-R inhibition remain unclear. CB(1)-R expression was validated in vascular smooth muscle cells (VSMCs) and aortic tissue of mice. Apolipoprotein E-deficient (ApoE-/-) mice were treated with cholesterol-rich diet and the selective CB(1)-R antagonist rimonabant or vehicle for 7 weeks. CB(1)-R inhibition had no effect on atherosclerotic plaque development, collagen content and macrophage infiltration but led to improved aortic endothelium-dependent vasodilation and decreased aortic reactive oxygen species (ROS) production and NADPH oxidase activity. Treatment of cultured VSMC with rimonabant resulted in reduced angiotensin II-mediated but not basal ROS production and NADPH oxidase activity. CB(1)-R inhibition with rimonabant and AM251 led to down-regulation of angiotensin II type 1 receptor (AT1-R) expression, whereas stimulation with the CB(1)-R agonist CP 55,940 resulted in AT1-R up-regulation, indicating that AT1-R expression is directly regulated by the CB(1)-R. CB(2)-R inhibition had no impact on AT1-R expression in VSMC. Consistently, CB(1)-R inhibition decreased aortic AT1-R expression in vivo. CB(1)-R inhibition leads to decreased vascular AT1-R expression, NADPH oxidase activity and ROS production in vitro and in vivo. This antioxidative effect is associated with improved endothelial function in ApoE-/- mice, indicating beneficial direct vascular effects of CB(1)-R inhibition.

  6. Comparison of the AT1-receptor blockers candesartan, irbesartan and losartan for inhibiting renal microvascular constriction

    Directory of Open Access Journals (Sweden)

    William F van Rodijnen


    Full Text Available Angiotensin II (Ang II type 1 (AT1 receptor blockers differ in their affinity for the AT1-receptor, suggesting a dissimilar potency for inhibiting Ang II-induced vascular constriction. In the present study, we compared the effects of candesartan, irbesartan and losartan on the renal microvascular constriction to locally-formed Ang II, using isolated, perfused hydronephrotic rat kidneys. Addition of 1 nmol/L angiotensin I (Ang I, the precursor of Ang II significantly reduced the diameters of interlobular arteries (ILAs; -47.6±2.6%, afferent arterioles (AAs; -43.6±2.3% and efferent arterioles (EAs; -31.6±2.4%. Candesartan and irbesartan were more potent in antagonising the constriction to Ang I than losartan. By contrast, candesartan and irbesartan differed only slightly in potency. After a washing period of 60 minutes with drug-free medium, a second application of Ang I failed to induce vasoconstriction only in candesartan-treated kidneys. Pretreatment of hydronephrotic kidneys with candesartan, to further explore its antagonistic properties, shifted the dose-response curves of Ang II approximately 2 log units to the right without reducing the maximal Ang II-induced constriction of ILAs, AAs or EAs. Additionally, dose-response curves of Ang II were similar after short (10 minutes and prolonged (60 minutes preincubation with candesartan. Our findings indicate that candesartan and irbesartan are more potent inhibitors of renal microvascular constriction to locally-formed Ang II than losartan. The inhibitory effect of candesartan is more prolonged, suggesting a slow dissociation from the AT1-receptor. Additionally, candesartan was found to block the Ang II-induced constriction of renal microvessels in a surmountable manner.

  7. Coinhibitory Receptor Expression and Immune Checkpoint Blockade: Maintaining a Balance in CD8+ T Cell Responses to Chronic Viral Infections and Cancer

    Directory of Open Access Journals (Sweden)

    Isobel S. Okoye


    Full Text Available In cancer and chronic viral infections, T cells are exposed to persistent antigen stimulation. This results in expression of multiple inhibitory receptors also called “immune checkpoints” by T cells. Although these inhibitory receptors under normal conditions maintain self-tolerance and prevent immunopathology, their sustained expression deteriorates T cell function: a phenomenon called exhaustion. Recent advances in cancer immunotherapy involve blockade of cytotoxic T lymphocyte antigen-4 and programmed cell death 1 in order to reverse T cell exhaustion and reinvigorate immunity, which has translated to dramatic clinical remission in many cases of metastatic melanoma and lung cancer. With the paucity of therapeutic vaccines against chronic infections such as HIV, HPV, hepatitis B, and hepatitis C, such adjunct checkpoint blockade strategies are required including the blockade of other inhibitory receptors such as T cell immunoreceptor with immunoglobulin (Ig and immunoreceptor tyrosine-based inhibitory motif domains, T cell Ig and mucin-domain containing-3, lymphocyte activation gene 3, and V-domain Ig-containing suppressor of T cell activation. The nature of different chronic viral infections and cancers is likely to influence the level, composition, and pattern of inhibitory receptors expressed by responding T cells. This will have implications for checkpoint antibody blockade strategies employed for treating tumors and chronic viral infections. Here, we review recent advances that provide a clearer insight into the role of coinhibitory receptor expression in T cell exhaustion and reveal novel antibody-blockade therapeutic targets for chronic viral infections and cancer. Understanding the mechanism of T cell exhaustion in response to chronic virus infections and cancer as well as the nature of restored T cell responses will contribute to further improvement of immune checkpoint blockade strategies.

  8. Improvement of endothelial dysfunction in experimental heart failure by chronic RAAS-blockade : ACE-inhibition or AT(1)-receptor blockade?

    NARCIS (Netherlands)

    Buikema, H; Pinto, YM; van Gilst, WH

    Chronic heart failure (CHF) is associated with endothelial dysfunction. Activation of the renin-angiotensin-aldosterone system (RAAS) is believed to be important in the deterioration of endodiehal dysfunction in CHF through stimulation of oxidative stress. Whereas angiotensin-converting enzyme

  9. Functional interaction of AT1 and AT2 receptors in fructose-induced insulin resistance and hypertension in rats. (United States)

    Hsieh, Po-Shiuan; Tai, Yueh-Hua; Loh, Ching-Hui; Shih, Kuang-Chung; Cheng, Wei-Tung; Chu, Chi-Hong


    The present study was performed to evaluate the potential role and functional interaction of angiotensin II AT1 and AT2 receptors (AT1R and AT2R) in the regulation of blood pressure and glucose homeostasis in fructose-induced insulin-resistant, hypertensive rats. Male Sprague-Dawley rats on fructose-enriched or regular diets for 4 weeks were subjected to 2-step euglycemic euinsulinemic (EEI) and euglycemic hyperinsulinemic (EHI) clamp studies with [3-3H]glucose infusion. After a 40-minute basal period, selective AT1R and AT2R antagonists, losartan (LOS, 10 mg/kg IV bolus) and PD123319 (PD, 50 microg/kg/min), alone or in combination were separately given to control and fructose-fed groups in the 2 clamp periods. The results showed that during the EEI period, LOS significantly reduced the elevated blood pressure in fructose-fed rats, whereas PD further increased fructose-induced high blood pressure. Coadministration of LOS and PD did not alter the elevated blood pressure in fructose-fed rats. Administration of LOS and/or PD failed to change the blood pressure in control rats. During the EHI period, blockade of both AT1R and AT2R eliminated the insulin-induced blood pressure elevation in control and fructose-fed rats. Hepatic glucose production (HGP) did not alter among groups in the basal and EEI periods. Insulin infusion (EHI period) markedly suppressed HGP in control rats, but this suppressive effect was significantly attenuated in fructose-fed rats. LOS administration further reduced the insulin-induced suppression of HGP in fructose-fed rats. The whole-body glucose uptakes (rates of glucose disappearance, Rd) during the basal and EEI periods were similar among groups. During the EHI period, Rd was markedly increased in all groups and the magnitude of increase was significantly greater in control rats than in fructose-fed rats except those with LOS treatment. LOS treatment also redirected Rd in favor of glycolysis in fructose rats, but not in control rats, during

  10. Glucagon increase after chronic AT1 blockade is more likely related to an indirect leptin-dependent than to a pancreatic α-cell-dependent mechanism. (United States)

    Mildner, Martin; Müller-Fielitz, Helge; Stölting, Ines; Jöhren, Olaf; Steckelings, Muscha; Raasch, Walter


    AT1 blockers (ARB) prevent diabetes by improving pancreatic β cell function. Less is known about whether α cells are affected although they express angiotensin II (AngII) receptors. We aimed to investigate glucagon release upon AngII stimulation. We determined glucagon release after AngII stimulation (0.01-100 μM) in α cells (InR1G9) and isolated murine islets. We determined plasma glucagon in rats that were chronically treated with AngII (9 μg/h) or the ARBs telmisartan (8 mg/kg/day) and candesartan (16 mg/kg/day) and correlated glucagon with additional hormones (e.g. leptin). Glucagon was only released from InR1G9 cells and islets at the highest AngII concentrations (>10 μM). This was not inhibited by losartan or PD123319. Ang(1-7) and AngIV were also almost ineffective. AngII did not alter glucagon secretion from islets. Plasma glucagon increased when obese Zucker rats were treated with AngII or candesartan and also when Sprague Dawley rats were treated with telmisartan in parallel to high-calorie feeding. Plasma glucagon and leptin negatively correlated in ARB-treated rats. The glucagon release from InR1G9 cells or islets after AngII, AngIV or Ang(1-7) is unspecific since it only occurs, if at all, after the highest concentrations and cannot be blocked by specific inhibitors. Thus, the AngII-dependent increase in plasma glucagon seems to be mediated by indirect mechanisms. The negative correlations between plasma leptin and glucagon confirm findings showing that leptin suppresses glucagon release, leading us to suppose that the increase in plasma glucagon is related to the decrease in leptin after ARB treatment.

  11. Repeated Blockade of NMDA Receptors during Adolescence Impairs Reversal Learning and Disrupts GABAergic Interneurons in Rat Medial Prefrontal Cortex

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    Jitao eLi


    Full Text Available Adolescence is of particular significance to schizophrenia, since psychosis onset typically occurs in this critical period. Based on the N-methyl-D-aspartate (NMDA receptor hypofunction hypothesis of schizophrenia, in this study, we investigated whether and how repeated NMDA receptor blockade during adolescence would affect GABAergic interneurons in rat medial prefrontal cortex (mPFC and mPFC-mediated cognitive functions. Specifically, adolescent rats were subjected to intraperitoneal administration of MK-801 (0.1, 0.2, 0.4 mg/kg, a non-competitive NMDA receptor antagonist, for 14 days and then tested for reference memory and reversal learning in the water maze. The density of parvabumin (PV-, calbindin (CB- and calretinin (CR-positive neurons in mPFC were analyzed at either 24 hours or 7 days after drug cessation. We found that MK-801 treatment delayed reversal learning in the water maze without affecting initial acquisition. Strikingly, MK-801 treatment also significantly reduced the density of PV+ and CB+ neurons, and this effect persisted for 7 days after drug cessation at the dose of 0.2 mg/kg. We further demonstrated that the reduction in PV+ and CB+ neuron densities was ascribed to a downregulation of the expression levels of PV and CB, but not to neuronal death. These results parallel the behavioral and neuropathological changes of schizophrenia and provide evidence that adolescent NMDA receptors antagonism offers a useful tool for unraveling the etiology of the disease.

  12. Targeted Blockade of TARP-g8-Associated AMPA Receptors: Anticonvulsant Activity with the Selective Antagonist LY3130481 (CERC-611). (United States)

    Witkin, Jeffrey M; Schober, Douglas A; Gleason, Scott D; Catlow, John T; Porter, Warren J; Reel, Jon; Jin, X; Hobbs, J; Gehlert, Donald; Gernert, Douglas L; Gardinier, Kevin M; Kato, Akihiko S; Ping, X; Smith, J L


    6-[(1S)-1-[1-[5-(2-hydroxyethoxy)-2-pyridyl]pyrazol-3-yl]ethyl]-3H-1,3-benzothiazol-2-one (LY3130481 or CERC-611) is a selective antagonist of AMPA receptors containing transmembrane AMPA receptor regulatory protein (TARP) g-8 that is under development for epilepsy. The present study provided a broad inquiry into its anticonvulsant properties. LY3130481 was anticonvulsant in multiple acute seizure provocation models in mice and rats. In addition, LY3130481 was effective against absence seizures in the GAERS genetic model and in the Frings mouse model. Likewise LY3130481 attenuated convulsions in mice and rats with long term induction of seizures (e.g., corneal, pentylenetetrazole, hippocampal, and amygdala kindled seizures). In slices of epileptic human cortex, LY3130481 significantly decreased neuronal firing frequencies. LY3130481 displaced from rat brain a radioligand specific for AMPA receptors associated with TARP g-8 whereas non-TARP-selective molecules did not. Binding was also observed in hippocampus freshly transected from a patient Taken as a whole, the findings reported here establish the broad anticonvulsant efficacy of LY3130481 indicating that blockade of AMPA receptors associated with TARP g-8 is sufficient for these protective effects. Copyright© Bentham Science Publishers; For any queries, please email at

  13. Toll-like receptor 3 blockade in rhinovirus-induced experimental asthma exacerbations

    DEFF Research Database (Denmark)

    Silkoff, Philip E; Flavin, Susan; Gordon, Robert


    BACKGROUND: Human rhinoviruses (HRVs) commonly precipitate asthma exacerbations. Toll-like receptor 3, an innate pattern recognition receptor, is triggered by HRV, driving inflammation that can worsen asthma. OBJECTIVE: We sought to evaluate an inhibitory mAb to Toll-like receptor 3, CNTO3157, on...

  14. 5-HT2A/2C receptor blockade regulates progenitor cell proliferation in the adult rat hippocampus. (United States)

    Jha, Shanker; Rajendran, Rajeev; Fernandes, Kimberly A; Vaidya, Vidita A


    Adult hippocampal neurogenesis is reported to be a target of antidepressants, drugs of abuse and animal models of depression, suggesting a role for this form of structural plasticity in psychopathology. Serotonergic neurotransmission, which is implicated in several psychiatric diseases, has been reported to regulate adult hippocampal neurogenesis. Amongst the serotonergic receptors, the serotonin2A/2C (5-HT2A/2C) receptors play an important role in the actions of antidepressants and the effects of hallucinogenic drugs of abuse. We have used the mitotic marker 5'-bromo-2-deoxyuridine to address the effects of the 5-HT2A/2C receptors on the proliferation of adult hippocampal progenitors following acute or chronic treatment with the hallucinogenic partial agonists, (+/-)-2,5-dimethoxy-4-iodoamphetamine (DOI) and lysergic acid diethylamide (LSD) and the antagonist, Ketanserin. Acute, and chronic, DOI and LSD treatments induced a strong behavioral activation, but did not alter adult hippocampal progenitor proliferation. In striking contrast, Ketanserin treatment resulted in a biphasic regulation with a significant decline (22%) in progenitor proliferation following a single treatment, and a robust increase (46%) observed following chronic administration. These results indicate that hallucinogenic drugs that primarily target the 5-HT2A/2C receptors, in contrast to other drugs of abuse, may not alter adult hippocampal neurogenesis. In addition, our results that enhanced adult hippocampal progenitor proliferation results from a sustained blockade of the 5-HT2A/2C receptors suggest that the 5-HT2A/2C receptors may be an important target for the neurogenic effects of antidepressant treatment.

  15. Initial evidence that GLP-1 receptor blockade fails to suppress postprandial satiety or promote food intake in humans. (United States)

    Melhorn, Susan J; Tyagi, Vidhi; Smeraglio, Anne; Roth, Christian L; Schur, Ellen A


    Glucagon-like peptide 1 (GLP-1) has incretin effects that are well-documented, but the independent role of GLP-1 action in human satiety perception is debated. We hypothesized that blockade of GLP-1 receptors would suppress postprandial satiety and increase voluntary food intake. After an overnight fast, eight normal weight participants (seven men, BMI 19-24.7 kg/m(2), age 19-29 year) were enrolled in a double-blind, placebo-controlled, randomized crossover study of the GLP-1 antagonist Exendin-[9-39] (Ex-9) to determine if the satiating effects of a meal are dependent on GLP-1 signaling in humans. Following a fasting blood draw, iv infusion of Ex-9 (600-750 pmol/kg/min) or saline began. Thirty minutes later, subjects consumed a standardized breakfast followed 90 min later (at the predicted time of maximal endogenous circulating GLP-1) by an ad libitum buffet meal to objectively measure satiety. Infusions ended once the buffet meal was complete. Visual analog scale ratings of hunger and fullness and serial assessments of plasma glucose, insulin, and GLP-1 concentrations were done throughout the experiment. Contrary to the hypothesis, during Ex-9 infusion subjects reported a greater decrease in hunger due to consumption of the breakfast (Ex-9 -62 ± 5; placebo -41 ± 9; P=0.01) than during placebo. There were no differences in ad libitum caloric intake between Ex-9 and placebo. Ex-9 increased glucose, insulin, and endogenous GLP-1, which may have counteracted any effects of Ex-9 infusion to block satiety signaling. Blockade of GLP-1 receptors failed to suppress subjective satiety following a standardized meal or increase voluntary food intake in healthy, normal-weight subjects. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. ACE inhibition is superior to angiotensin receptor blockade for renography in renal artery stenosis

    Energy Technology Data Exchange (ETDEWEB)

    Karanikas, Georgios; Becherer, Alexander; Wiesner, Karoline; Dudczak, Robert; Kletter, Kurt [Department of Nuclear Medicine, University of Vienna (Austria)


    Angiotensin converting enzyme (ACE) inhibitors as well as angiotensin II receptor antagonists are able to prevent the vasoconstrictive effect of angiotensin II on the efferent renal vessels, which is believed to play an important role in renovascular hypertension. This effect is assumed to be essential for the demonstration of renovascular hypertension by captopril renography. In this study, renographic changes induced by captopril and the AT1 receptor antagonist valsartan were compared in patients with a high probability for renovascular hypertension. Twenty-five patients with 33 stenosed renal arteries (grade of stenosis >50%) and hypertension were studied. Captopril, valsartan and baseline renography were performed within 48 h using technetium-99m mercaptoacetyltriglycine. Blood pressure was monitored, plasma renin concentration before and after intervention was determined and urinary flow was estimated from the urinary output of the hydrated patients. Alterations in renographic curves after intervention were evaluated according to the Santa Fe consensus on ACE inhibitor renography. Captopril renography was positive, indicating renovascular hypertension, in 25 of the 33 stenosed vessels, whereas valsartan renography was positive in only ten. Blood pressure during captopril and valsartan renography was not different; reduction in blood pressure was the same after valsartan and captopril. Plasma renin concentration was comparable for valsartan and captopril studies, showing suppressed values after intervention in as many as 12 of the 25 patients. Urinary flow after valsartan was higher than after captopril (P<0.05). However, this difference could not explain the markedly higher sensitivity of captopril compared with valsartan in demonstrating renal artery stenosis. In 14 of the 25 patients, blood pressure response to revascularisation was monitored, showing a much better predictive value for captopril renography. It is concluded that captopril renography is much

  17. Lithium attenuated the behavioral despair induced by acute neurogenic stress through blockade of opioid receptors in mice. (United States)

    Khaloo, Pegah; Sadeghi, Banafshe; Ostadhadi, Sattar; Norouzi-Javidan, Abbas; Haj-Mirzaian, Arya; Zolfagharie, Samira; Dehpour, Ahmad-Reza


    Major depressive disorder is disease with high rate of morbidity and mortality. Stressful events lead to depression and they can be used as a model of depression in rodents. In this study we aimed to investigate whether lithium modifies the stressed-induced depression through blockade of opioid receptors in mice. We used foot shock stress as stressor and forced swimming test (FST), tail suspension test (TST) and open field test (OFT) to evaluation the behavioral responses in mice. We also used naltrexone hydrochloride (as opioid receptor antagonist), and morphine (as opioid receptor agonist). Our results displayed that foot-shock stress significantly increased the immobility time in TST and FST but it could not change the locomotor behavior in OFT. When we combined the low concentrations of lithium and naltrexone a significant reduction in immobility time was seen in the FST and TST in comparison with control foot-shock stressed group administered saline only. Despite the fact that our data showed low concentrations of lithium, when administered independently did not significantly affect the immobility time. Also our data indicated that concurrent administration of lithium and naltrexone had no effect on open field test. Further we demonstrated that simultaneous administration of morphine and lithium reverses the antidepressant like effect of active doses of lithium. Our data acclaimed that we lithium can augment stressed-induced depression and opioid pathways are involved in this action. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  18. Chronic blockade of the AT2 receptor with PD123319 impairs insulin signaling in C57BL/6 mice. (United States)

    Muñoz, M C; Burghi, V; Miquet, J G; Cervino, I A; Quiroga, D T; Mazziotta, L; Dominici, F P


    The renin-angiotensin system modulates insulin action. Angiotensin type 1 receptor exerts a deleterious effects while the angiotensin type 2 receptor (AT2R) appears to have beneficial effects providing protection against insulin resistance and type 2 diabetes. Although recent reports indicate that agonism of AT2R ameliorates diabetes and insulin resistance, the phenotype of AT2R-knockout mice seems to be controversial relating this aspect. Thus, in this study we have explored the role of AT2R in the control of insulin action. To that end, C57Bl/6 mice were administered the synthetic AT2R antagonist PD123319 for 21days (10mg/kg/day ip); vehicle treated animals were used as control. Glucose tolerance, metabolic parameters, in vivo insulin signaling in main insulin-target tissues as well as levels of adiponectin, TNF-α, MCP-1 and IL-6 in adipose tissue were assessed. AT2R blockade with PD123319 induced a marginal effect on glucose homeostasis but an important reduction in the insulin-induced phosphorylation of the insulin receptor and Akt in both liver and adipose tissue. Insulin signaling in skeletal muscle remained unaltered after treatment with PD123319, which could explain the minimal effect on glucose homeostasis induced by PD123319. Our current results reinforce the notion that the AT2R has a physiological role in the conservation of insulin action. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. [Post-training N-methyl-D-aspartate receptor blockade facilitates retention of acquired spatial memory in rats]. (United States)

    Shinohara, Keisuke; Hata, Toshimichi


    We investigated the effect of a post-training chronic infusion of N-methyl-D-aspartate (NMDA) receptor blocker on retention of spatial reference memory in rats. In Experiment 1, we trained 4 groups of rats for 4 days (4 trials/ day) in the Morris water maze task. In a single probe trial after retention intervals of 1, 7, 14, and 28 days, the 1-day group showed more goal crossings than shown by the other 3 groups. In Experiment 2, a chronic infusion of the NMDA receptor antagonist D-2-amino-5-phosphonovaleric acid (D-AP5) or a control vehicle into the lateral ventricle was initiated 1 day after the training session, and continued for 6 days. In the subsequent probe trial (7 days after training), the rats that had received the D-AP5 infusion showed significantly more goal crossings than the controls. These findings suggest that an NMDA receptor blockade following acquisition facilitates retention of spatial reference memory.

  20. Platelet glycoprotein IIb/IIIa receptor blockade in coronary artery disease

    National Research Council Canada - National Science Library

    Lincoff, A.Michael; Califf, Robert M; Topol, Eric J


    .... Intravenous agents directed against this receptor include the chimeric monoclonal antibody fragment abciximab, the peptide inhibitor eptifibatide and nonpeptide mimetics tirofiban and lamifiban...

  1. Influence of autoantibodies against AT1 receptor and AGTR1 polymorphisms on candesartan-based antihypertensive regimen: results from the study of optimal treatment in hypertensive patients with anti-AT1-receptor autoantibodies trial. (United States)

    Sun, Yanxiang; Liao, Yuhua; Yuan, Yong; Feng, Li; Ma, Shihui; Wei, Feng; Wang, Min; Zhu, Feng


    The autoantibodies against angiotensin AT1 receptors (AT1-AAs) in patients with essential hypertension exhibited an agonistic action like angiotensin II and maintained high blood pressure (BP). Angiotensin II receptor gene (AGTR1) polymorphisms were associated with BP response to RAS inhibition in the hypertensive population. Furthermore, the BP response to AT1 receptor blockers varied significantly among individuals with hypertension. We hypothesized that the polymorphisms of the AGTR1 and AT1-AAs might affect antihypertensive response to AT1 receptor blockers based in patients with primary hypertension. Patients who received a candesartan-based regimen came from the SOT-AT1 study (Study of Optimal Treatment in Hypertensive Patients with Anti-AT1-Receptor Autoantibodies). The established enzyme-labeled immunosorbent assay was used to detect AT1-AAs in the sera of the patients. Genotype 3 single nucleotide polymorphisms in AGTR1 gene was used by DNA sequencing. The correlations among AT1-AAs, AGTR1 gene polymorphisms or haplotypes, and the antihypertensive effect candesartan-based were analyzed using SPSS. The percentage of systolic BP reduction that was candesartan-based was greater in AT1-AA positive groups than in AT1-AA negative ones (21 ± 8 vs. 18 ± 9; P = .001). Meanwhile, systolic BP reduction that was candesartan-based was more significant in the group of rs5186 AC genotypes than AA homozygotes after adjusting for other confounding factors (37.55 ± 13.7 vs. 32.47 ± 17.27 mm Hg; adjusted P = .028). Furthermore, haplotypes (GCC) and (AAC) had impacts on the antihypertensive effect of candesartan therapy. The AT1-AAs, AGTR1 gene polymorphisms and haplotypes solely or jointly have influences on candesartan-based antihypertensive response in patients with primary hypertension. Copyright © 2014 American Society of Hypertension. Published by Elsevier Inc. All rights reserved.

  2. Mechanism of A2 adenosine receptor activation. I. Blockade of A2 adenosine receptors by photoaffinity labeling

    Energy Technology Data Exchange (ETDEWEB)

    Lohse, M.J.; Klotz, K.N.; Schwabe, U.


    It has previously been shown that covalent incorporation of the photoreactive adenosine derivative (R)-2-azido-N6-p-hydroxy-phenylisopropyladenosine ((R)-AHPIA) into the A1 adenosine receptor of intact fat cells leads to a persistent activation of this receptor, resulting in a reduction of cellular cAMP levels. In contrast, covalent incorporation of (R)-AHPIA into human platelet membranes, which contain only stimulatory A2 adenosine receptors, reduces adenylate cyclase stimulation via these receptors. This effect of (R)-AHPIA is specific for the A2 receptor and can be prevented by the adenosine receptor antagonist theophylline. Binding studies indicate that up to 90% of A2 receptors can be blocked by photoincorporation of (R)-AHPIA. However, the remaining 10-20% of A2 receptors are sufficient to mediate an adenylate cyclase stimulation of up to 50% of the control value. Similarly, the activation via these 10-20% of receptors occurs with a half-life that is only 2 times longer than that in control membranes. This indicates the presence of a receptor reserve, with respect to both the extent and the rate of adenylate cyclase stimulation. These observations require a modification of the models of receptor-adenylate cyclase coupling.

  3. 5-HT6 receptor blockade regulates primary cilia morphology in striatal neurons. (United States)

    Brodsky, Matthew; Lesiak, Adam J; Croicu, Alex; Cohenca, Nathalie; Sullivan, Jane M; Neumaier, John F


    The 5-HT6 receptor has been implicated in a variety of cognitive processes including habitual behaviors, learning, and memory. It is found almost exclusively in the brain, is expressed abundantly in striatum, and localizes to neuronal primary cilia. Primary cilia are antenna-like, sensory organelles found on most neurons that receive both chemical and mechanical signals from other cells and the surrounding environment; however, the effect of 5-HT6 receptor function on cellular morphology has not been examined. We confirmed that 5-HT6 receptors were localized to primary cilia in wild-type (WT) but not 5-HT6 knockout (5-HT6KO) in both native mouse brain tissue and primary cultured striatal neurons then used primary neurons cultured from WT or 5-HT6KO mice to study the function of these receptors. Selective 5-HT6 antagonists reduced cilia length in neurons cultured from wild-type mice in a concentration and time-dependent manner without altering dendrites, but had no effect on cilia length in 5-HT6KO cultured neurons. Varying the expression levels of heterologously expressed 5-HT6 receptors affected the fidelity of ciliary localization in both WT and 5-HT6KO neurons; overexpression lead to increasing amounts of 5-HT6 localization outside of the cilia but did not alter cilia morphology. Introducing discrete mutations into the third cytoplasmic loop of the 5-HT6 receptor greatly reduced, but did not entirely eliminate, trafficking of the 5-HT6 receptor to primary cilia. These data suggest that blocking 5-HT6 receptor activity reduces the length of primary cilia and that mechanisms that regulate trafficking of 5-HT6 receptors to cilia are more complex than previously thought. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Bradykinin receptor blockade restores the baroreflex control of renal sympathetic nerve activity in cisplatin-induced renal failure rats. (United States)

    Abdulla, M H; Duff, M; Swanton, H; Johns, E J


    This study investigated the effect of renal bradykinin B1 and B2 receptor blockade on the high- and low-pressure baroreceptor reflex regulation of renal sympathetic nerve activity (RSNA) in rats with cisplatin-induced renal failure. Cisplatin (5 mg/kg) or saline was given intraperitoneally 4 days prior to study. Following chloralose/urethane anaesthesia, rats were prepared for measurement of mean arterial pressure (MAP), heart rate and RSNA and received intrarenal infusions of either Lys-[des-Arg9 , Leu8 ]-bradykinin (LBK), a bradykinin B1 receptor blocker, or bradyzide (BZ), a bradykinin B2 receptor blocker. RSNA baroreflex gain curves and renal sympatho-inhibitory responses to volume expansion (VE) were obtained. In the control and renal failure groups, basal MAP (89 ± 3 vs. 80 ± 8 mmHg) and RSNA (2.0 ± 0.3 vs. 1.7 ± 0.6 μV.s) were similar but HR was lower in the latter group (331 ± 8 vs. 396 ± 9 beats/min). The baroreflex gain for RSNA in the renal failure rats was 39% (P renal failure rats. Intrarenal LBK infusion in the renal failure rats normalized the VE induced renal sympatho-inhibition whereas BZ only partially restored the response. These findings suggest that pro-inflammatory bradykinin acting at different receptors within the kidney generates afferent neural signals which impact differentially within the central nervous system on high- and low-pressure regulation of RSNA. © 2016 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

  5. Effect of acute aerobic exercise and histamine receptor blockade on arterial stiffness in African Americans and Caucasians. (United States)

    Yan, Huimin; Ranadive, Sushant M; Lane-Cordova, Abbi D; Kappus, Rebecca M; Behun, Michael A; Cook, Marc D; Woods, Jeffrey A; Wilund, Kenneth R; Baynard, Tracy; Halliwill, John R; Fernhall, Bo


    African Americans (AA) exhibit exaggerated central blood pressure (BP) and arterial stiffness measured by pulse wave velocity (PWV) in response to an acute bout of maximal exercise compared with Caucasians (CA). However, whether potential racial differences exist in central BP, elastic, or muscular arterial distensibility after submaximal aerobic exercise remains unknown. Histamine receptor activation mediates sustained postexercise hyperemia in CA but the effect on arterial stiffness is unknown. This study sought to determine the effects of an acute bout of aerobic exercise on central BP and arterial stiffness and the role of histamine receptors, in AA and CA. Forty-nine (22 AA, 27 CA) young and healthy subjects completed the study. Subjects were randomly assigned to take either histamine receptor antagonist or control placebo. Central blood BP and arterial stiffness measurements were obtained at baseline, and at 30, 60, and 90 min after 45 min of moderate treadmill exercise. AA exhibited greater central diastolic BP, elevated brachial PWV, and local carotid arterial stiffness after an acute bout of submaximal exercise compared with CA, which may contribute to their higher risk of cardiovascular disease. Unexpectedly, histamine receptor blockade did not affect central BP or PWV in AA or CA after exercise, but it may play a role in mediating local carotid arterial stiffness. Furthermore, histamine may mediate postexercise carotid arterial dilation in CA but not in AA. These observations provide evidence that young and healthy AA exhibit an exaggerated hemodynamic response to exercise and attenuated vasodilator response compared with CA.NEW & NOTEWORTHY African Americans are at greater risk for developing cardiovascular disease than Caucasians. We are the first to show that young and healthy African Americans exhibit greater central blood pressure, elevated brachial stiffness, and local carotid arterial stiffness following an acute bout of submaximal exercise

  6. Improvement of Chicken Primordial Germ Cell Maintenance In Vitro by Blockade of the Aryl Hydrocarbon Receptor Endogenous Activity. (United States)

    Pérez Sáez, Juan M; Bussmann, Leonardo E; Barañao, J Lino; Bussmann, Ursula A


    Primordial germ cells (PGCs) are the undifferentiated progenitors of gametes. Germline competent PGCs can be developed as a cell-based system for genetic modification in chickens, which provides a valuable tool for transgenic technology with both research and industrial applications. This implies manipulation of PGCs, which, in recent years, encouraged a lot of research focused on the study of PGCs and the way of improving their culture. The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that besides mediating toxic responses to environmental contaminants plays pivotal physiological roles in various biological processes. Since a novel compound that acts as an antagonist of this receptor has been reported to promote expansion of hematopoietic stem cells, we conducted the present study with the aim of determining whether addition of an established AHR antagonist to the standard culture medium used nowadays for in vitro chicken PGCs culture improves ex vivo expansion. We have found that addition of α-naphthoflavone in culture medium promotes the amplification of undifferentiated cells and that this effect is exerted by the blockade of AHR action. Our results constitute the first report of the successful use of a readily available AHR antagonist to improve avian PGCs expansion, and they further extend the knowledge of the effects of AHR modulation in undifferentiated cells.

  7. Selective Blockade of the Ubiquitous Checkpoint Receptor CD47 Is Enabled by Dual-Targeting Bispecific Antibodies. (United States)

    Dheilly, Elie; Moine, Valéry; Broyer, Lucile; Salgado-Pires, Susana; Johnson, Zoë; Papaioannou, Anne; Cons, Laura; Calloud, Sébastien; Majocchi, Stefano; Nelson, Robert; Rousseau, François; Ferlin, Walter; Kosco-Vilbois, Marie; Fischer, Nicolas; Masternak, Krzysztof


    CD47 is a ubiquitously expressed immune checkpoint receptor that is often upregulated in cancer. CD47 interacts with its counter-receptor SIRPα on macrophages and other myeloid cells to inhibit cancer cell phagocytosis and drive immune evasion. To overcome tolerability and "antigen sink" issues arising from widespread CD47 expression, we generated dual-targeting bispecific antibodies that selectively block the CD47-SIRPα interaction on malignant cells expressing a specific tumor-associated antigen; e.g., CD19 or mesothelin. These bispecific κλ bodies are fully human, native IgG1 molecules, combining tumor targeting and selective CD47 blockade with immune activating mechanisms mediated by the Fc portion of the antibody. CD47-neutralizing κλ bodies efficiently kill cancer cells in vitro and in vivo but interact only weakly with healthy cells expressing physiological levels of CD47. Accordingly, a κλ body administered to non-human primates showed a typical IgG pharmacokinetic profile and was well tolerated. Importantly, κλ bodies preserve their tumoricidal capabilities in the presence of a CD47 antigen sink. Thus, dual-targeting κλ bodies allow for efficacious yet safe targeting of CD47 in cancer. Such a bispecific design could be applied to limit the extent of neutralization of other ubiquitously expressed therapeutic targets. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  8. Purinergic receptor blockade in the retrotrapezoid nucleus attenuates the respiratory chemoreflexes in awake rats. (United States)

    Barna, B F; Takakura, A C; Mulkey, D K; Moreira, T S


    Recent evidence suggests that adenosine triphosfate (ATP)-mediated purinergic signalling at the level of the rostral ventrolateral medulla contributes to both central and peripheral chemoreceptor control of breathing and blood pressure: neurones in the retrotrapezoid nucleus (RTN) function as central chemoreceptors in part by responding to CO2 -evoked ATP release by activation of yet unknown P2 receptors, and nearby catecholaminergic C1 neurones regulate blood pressure responses to peripheral chemoreceptor activation by a P2Y1 receptor-dependent mechanism. However, potential contributions of purinergic signalling in the RTN to cardiorespiratory function in conscious animals have not been tested. Cardiorespiratory activity of unrestrained awake rats was measured in response to RTN injections of ATP, and during exposure to hypercapnia (7% CO2 ) or hypoxia (8% O2 ) under control conditions and after bilateral RTN injections of P2 receptor blockers (PPADS or MRS2179). Unilateral injection of ATP into the RTN increased cardiorespiratory output by a P2-receptor-dependent mechanism. We also show that bilateral RTN injections of a non-specific P2 receptor blocker (pyridoxal-phosphate-6-azophenyl-2',4'-disulfonate (PPADS) reduced the ventilatory response to hypercapnia (7% CO2 ) and hypoxia (8% O2 ) in unanesthetized rats. Conversely, bilateral injections of a specific P2Y1 receptor blocker (MRS2179) into the RTN had no measurable effect on ventilatory responses elicited by hypercapnia or hypoxia. These data exclude P2Y1 receptor involvement in the chemosensory control of breathing at the level of the RTN and show that ATP-mediated purinergic signalling contributes to central and peripheral chemoreflex control of breathing and blood pressure in awake rats. © 2015 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

  9. Both genetic deletion and pharmacological blockade of lysophosphatidic acid LPA1 receptor results in increased alcohol consumption. (United States)

    Castilla-Ortega, Estela; Pavón, Francisco Javier; Sánchez-Marín, Laura; Estivill-Torrús, Guillermo; Pedraza, Carmen; Blanco, Eduardo; Suárez, Juan; Santín, Luis; Rodríguez de Fonseca, Fernando; Serrano, Antonia


    Lysophosphatidic acid species (LPA) are lipid bioactive signaling molecules that have been recently implicated in the modulation of emotional and motivational behaviors. The present study investigates the consequences of either genetic deletion or pharmacological blockade of lysophosphatidic acid receptor-1 (LPA1) in alcohol consumption. The experiments were performed in alcohol-drinking animals by using LPA1-null mice and administering the LPA1 receptor antagonist Ki16425 in both mice and rats. In the two-bottle free choice paradigm, the LPA1-null mice preferred the alcohol more than their wild-type counterparts. Whereas the male LPA1-null mice displayed this higher preference at all doses tested, the female LPA1-null mice only consumed more alcohol at 6% concentration. The male LPA1-null mice were then further characterized, showing a notably increased ethanol drinking after a deprivation period and a reduced sleep time after acute ethanol administration. In addition, LPA1-null mice were more anxious than the wild-type mice in the elevated plus maze test. For the pharmacological experiments, the acute administration of the antagonist Ki16425 consistently increased ethanol consumption in both wild-type mice and rats; while it did not modulate alcohol drinking in the LPA1-null mice and lacked intrinsic rewarding properties and locomotor effects in a conditioned place preference paradigm. In addition, LPA1-null mice exhibited a marked reduction on the expression of glutamate-transmission-related genes in the prefrontal cortex similar to those described in alcohol-exposed rodents. Results suggest a relevant role for the LPA/LPA1 signaling system in alcoholism. In addition, the LPA1-null mice emerge as a new model for genetic vulnerability to excessive alcohol drinking. The pharmacological manipulation of LPA1 receptor arises as a new target for the study and treatment of alcoholism. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Chronic blockade of melanocortin receptors alleviates allodynia in rats with neuropathic pain

    NARCIS (Netherlands)

    Gispen, W.H.; Vrinten, D.H.; Adan, R.A.H.; Groen, G.J.


    We investigated the involvement of the spinal cord melanocortin (MC) system in neuropathic pain. Because we recently demonstrated that MC receptor ligands acutely alter nociception in an animal model of neuropathic pain, in this study we tested whether chronic administration was also effective. We

  11. The effect of purinergic P2 receptor blockade on skeletal muscle exercise hyperemia in miniature swine

    DEFF Research Database (Denmark)

    Mortensen, Stefan Peter; McAllister, R M; Yang, H T


    -microsphere technique and systemic hemodynamics before and after arterial infusion of the P2 receptor antagonist reactive blue 2 during treadmill exercise (5.2 km/h, ~60 % VO2max) and arterial ATP infusion in female Yucatan miniature swine (~29 kg). RESULTS: Mean blood flow during exercise from the 16 sampled skeletal...

  12. Effect of adenosine1-receptor blockade on renin release from rabbit isolated perfused juxtaglomerular apparatus

    DEFF Research Database (Denmark)

    Weihprecht, H; Lorenz, J N; Schnermann, J


    ,3-dipropylxanthine (CPX) on renin release from single isolated rabbit JGAs with macula densa perfused. The A1-receptor agonist, N6-cyclohexyladenosine (CHA), applied in the bathing solution at 10(-7) M, was found to inhibit renin secretion, an effect that was completely blocked by adding CPX (10(-5) M) to the bath...

  13. Appearance of antidepressant-like effect by sildenafil in rats after central muscarinic receptor blockade: evidence from behavioural and neuro-receptor studies. (United States)

    Brink, C B; Clapton, J D; Eagar, B E; Harvey, B H


    The phosphodiesterase (PDE) 5 inhibitor sildenafil has been shown to display psychotropic actions in humans and animals, and has been used for the treatment of antidepressant-associated erectile dysfunction. However, its effects on the neurobiology of depression are unknown. Nitric oxide (NO)-cyclic guanosine monophosphate (cGMP) inhibition is anti-depressant in animals, and increasing cGMP with sildenafil is anxiogenic in rodents. Substantial cholinergic-nitrergic interaction exists in the brain, while sildenafil shows modulatory actions on cholinergic transmission. Depression is also associated with increased cholinergic drive. Here we report that sildenafil increases muscarinic acetylcholine receptor (mAChR) signaling in human neuroblastoma cells. We also show that fluoxetine (20 mg/kg/day x 7 days), as well as a combination of sildenafil (10 mg/kg/day x 7 days) plus the antimuscarinic atropine (1 mg/kg/day x 7 days) demonstrates significant, comparable antidepressant-like effects in the rat forced swim test (FST) and also reduces cortical beta-adrenergic receptor (beta-AR) density, while sildenafil or atropine alone did not. Importantly, sildenafil did not modify fluoxetine's response. Sildenafil thus demonstrates antidepressant-like effects but only after central muscarinic receptor blockade, providing evidence for cholinergic-nitrergic interactions in the neurobiology of depression.

  14. Blockade of endothelin B receptor improves the efficacy of levetiracetam in chronic epileptic rats. (United States)

    Ko, Ah-Reum; Kang, Tae-Cheon


    To elucidate the mechanisms that regulate p-glycoprotein (PGP) expression and function in pharmacoresistant epilepsy, we investigated the effect of an ETB receptor antagonist (BQ788) and a p38 mitogen-activated protein kinase (p38MAPK) inhibitor (SB202190) on intractable seizures in chronic epileptic rats. Lithium-pilocarpine-induced chronic epileptic rats were used in the present study. Animals were given levetiracetam (LEV), LEV + SB202190, LEV + BQ788, SB202190 or BQ788 over a 3-day period using an osmotic pump. Seizure activity was recorded by video-EEG monitoring with 2h of recording per day at the same time of day. We also performed western blot after EEG analysis. Compared to control animals, PGP, ETB receptor and p38MAPK expression was increased in the hippocampus of epileptic animals. Neither SB202190 nor BQ788 affected the spontaneous seizure activity in epileptic rats. Three of ten rats were responders and achieved complete seizure control or significant reduction in seizure activity by LEV. In four of ten rats, seizure frequency was unaltered by LEV (non-responders). LEV + SB202190 reduced seizure duration, but not seizure frequency, in both responders and non-responders. LEV + BQ788 alleviated seizure frequency and seizure duration in both responders and non-responders. Compared to responders, PGP and ETB receptor expression was enhanced in the hippocampus of non-responders. To the best of our knowledge, these findings are the first indications of the role of ETB receptor in pharmacoresistant epilepsy. Therefore, the present data suggest that the regulation of the ETB receptor-mediated signaling pathway may be important for identification of new therapeutic strategies for improving antiepileptic drug efficacy. Copyright © 2015 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

  15. The modified Geller-Seifter test in rats was insensitive to GABAB receptor positive modulation or blockade, or 5-HT1A receptor activation. (United States)

    Paterson, Neil E; Hanania, Taleen


    Both the GABA(B) receptor positive modulator GS39783 and the GABA(B) receptor antagonist CGP46381 exhibit anxiolytic-like properties in animal models. In the present studies, the effects of GS39783 and CGP46381 in the modified Geller-Seifter task were assessed. First, the predictive validity of the task was confirmed by assessing the effects of multiple anxiolytic and non-anxiolytic compounds on punished and unpunished responding. Rats were trained in the modified Geller-Seifter task. After successful acquisition of the task, chlordiazepoxide, diazepam, MPEP, haloperidol, GS39783, 8-OH-DPAT, alprazolam and CGP46381 were tested consecutively. For each test compound, doses were administered in a randomized, counter-balanced, within-subjects design. Drug tests were performed only when rats exhibited baseline performance (the punished and time-out response rates were less than 10% of the unpunished response rate). Chlordiazepoxide, diazepam, alprazolam and MPEP released punished responding with variable effects on unpunished responding. Haloperidol had a small but significant effect on punished responding at an intermediate dose, and decreased unpunished responding at the highest dose tested. In contrast, administration of the GABA(B) receptor positive modulator GS398783 or the GABA(B) receptor antagonist CGP46381 at doses up to 30 mg/kg had no effects on either punished or unpunished responding. The 5-HT(1A) agonist 8-OH-DPAT did not release punished responding, but significantly decreased unpunished responding at the highest dose tested. The modified Geller-Seifter task generally exhibits good predictive validity for anxiolytic-like compounds. Neither GABA(B) receptor positive allosteric modulation nor blockade exhibited anxiolytic-like properties in the modified Geller-Seifter task. The 5-HT(1A) partial agonist buspirone was similarly ineffective. Copyright 2009 Elsevier B.V. All rights reserved.

  16. Analysis of Transmembrane Domains 1 and 4 of the Human Angiotensin II AT1 Receptor by Cysteine-scanning Mutagenesis* (United States)

    Yan, Liping; Holleran, Brian J.; Lavigne, Pierre; Escher, Emanuel; Guillemette, Gaétan; Leduc, Richard


    The octapeptide hormone angiotensin II (AngII) exerts a wide variety of cardiovascular effects through the activation of the AT1 receptor, which belongs to the G protein-coupled receptor superfamily. Like other G protein-coupled receptors, the AT1 receptor possesses seven transmembrane domains that provide structural support for the formation of the ligand-binding pocket. Here, we investigated the role of the first and fourth transmembrane domains (TMDs) in the formation of the binding pocket of the human AT1 receptor using the substituted-cysteine accessibility method. Each residue within the Phe-28(1.32)–Ile-53(1.57) fragment of TMD1 and Leu-143(4.40)–Phe-170(4.67) fragment of TMD4 was mutated, one at a time, to a cysteine. The resulting mutant receptors were expressed in COS-7 cells, which were subsequently treated with the charged sulfhydryl-specific alkylating agent methanethiosulfonate ethylammonium (MTSEA). This treatment led to a significant reduction in the binding affinity of TMD1 mutants M30C(1.34)-AT1 and T33C(1.37)-AT1 and TMD4 mutant V169C(4.66)-AT1. Although this reduction in binding of the TMD1 mutants was maintained when examined in a constitutively active receptor (N111G-AT1) background, we found that V169C(4.66)-AT1 remained unaffected when treated with MTSEA compared with untreated in this context. Moreover, the complete loss of binding observed for R167C(4.64)-AT1 was restored upon treatment with MTSEA. Our results suggest that the extracellular portion of TMD1, particularly residues Met-30(1.34) and Thr-33(1.37), as well as residues Arg-167(4.64) and Val-169(4.66) at the junction of TMD4 and the second extracellular loop, are important binding determinants within the AT1 receptor binding pocket but that these TMDs undergo very little movement, if at all, during the activation process. PMID:19940150

  17. Blockade of patch-based μ opioid receptors in the striatum attenuates methamphetamine-induced conditioned place preference and reduces activation of the patch compartment. (United States)

    Horner, Kristen A; Logan, Mary Caroline; Fisher, Trevor J; Logue, Jordan B


    The behavioral effects of methamphetamine (METH) are mediated by the striatum, which is divided into the patch compartment, which mediates limbic and reward functions, and the matrix compartment, which mediates sensorimotor tasks. METH treatment results in repetitive behavior that is related to enhanced relative activation of the patch versus the matrix compartment. The patch, but not the matrix compartment contains a high density of μ opioid receptors, and localized blockade of patch-based μ opioid receptors attenuates METH-induced patch-enhanced activity and repetitive behaviors. Numerous studies have examined patch-enhanced activity and the contribution of patch-associated μ opioid receptors to METH-induced repetitive behavior, but it is not known whether patch-enhanced activity occurs during METH-mediated reward, nor is it known if patch-based μ opioid receptors contribute to METH reward. The goals of this study were to determine if blockade of patch-based μ opioid receptors alters METH-induced conditioned place preference (CPP), as well activation of the patch and matrix compartments following METH-mediated CPP. A biased conditioning paradigm was used to assess CPP, and conditioning occurred over an 8-d period. Animals were bilaterally infused in the striatum with the μ-specific antagonist CTAP or vehicle prior to conditioning. Animals were tested for preference 24h after the last day of conditioning, sacrificed and the brains processed for immunohistochemistry. Blockade of patch-based μ opioid receptors reduced METH-induced CPP, and reduced patch-enhanced c-Fos expression in the striatum following METH-mediated CPP. These data indicate that patch-enhanced activity is associated with METH-mediated reward and patch-based μ opioid receptors contribute to this phenomenon. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Effects of dopamine D1 receptor blockade in the prelimbic prefrontal cortex or lateral dorsal striatum on frontostriatal function in Wistar and Spontaneously Hypertensive Rats


    Gauthier, Jamie M.; Tassin, David H.; Dwoskin, Linda P.; Kantak, Kathleen M.


    Attention Deficit Hyperactivity Disorder (ADHD) is associated with dysfunctional prefrontal and striatal circuitry and dysregulated dopamine neurotransmission. Spontaneously Hypertensive Rats (SHR), a heuristically useful animal model of ADHD, were evaluated against normotensive Wistar (WIS) controls to determine whether dopamine D1 receptor blockade of either prelimbic prefrontal cortex (plPFC) or lateral dorsal striatum (lDST) altered learning functions of both interconnected sites. A strat...

  19. Angiotensin receptor blockade in acute stroke. The Scandinavian Candesartan Acute Stroke Trial

    DEFF Research Database (Denmark)

    Sandset, Else Charlotte; Murray, Gordon; Boysen, Gudrun


    BACKGROUND: Elevated blood pressure following acute stroke is common, and yet early antihypertensive treatment is controversial. ACCESS suggested a beneficial effect of the angiotensin receptor blocker candesartan in the acute phase of stroke, but these findings need to be confirmed in new, large......-European countries: Norway, Sweden, Denmark, Belgium, Germany, Poland, Lithuania, Estonia and Finland. STUDY OUTCOMES: There are two co-primary effect variables: • Functional status at 6-months, measured by the modified Rankin Scale, and • vascular death, myocardial infarction or stroke during the first 6-months...

  20. Normotensive sodium loading in conscious dogs: Regulation of renin secretion during beta receptor blockade

    DEFF Research Database (Denmark)

    Bie, Peter; Mølstrøm, Simon; Wamberg, Søren


    Cl (20 micromol/kg/min for 180 min, NaLoad) during regular or low-sodium diet (0.03 mmol/kg/d, LowNa) with and without metoprolol (2 mg/kg plus 0.9 mg/kg/h). Vasopressin V2 receptors were blocked by Otsuka compound OPC31260 to facilitate clearance measurements. Body fluid volume was maintained by servo......-mediated effects of norepinephrine. Low-sodium diet augments vasopressin secretion while ANP secretion is reduced. Key words: blood pressure,, angiotensin, aldosterone, natriuresis....

  1. Colony-Stimulating Factor 1 Receptor Blockade Inhibits Tumor Growth by Altering the Polarization of Tumor-Associated Macrophages in Hepatocellular Carcinoma. (United States)

    Ao, Jian-Yang; Zhu, Xiao-Dong; Chai, Zong-Tao; Cai, Hao; Zhang, Yuan-Yuan; Zhang, Ke-Zhi; Kong, Ling-Qun; Zhang, Ning; Ye, Bo-Gen; Ma, De-Ning; Sun, Hui-Chuan


    Colony-stimulating factor-1 (CSF-1) and its receptor, CSF-1R, regulate the differentiation and function of macrophages and play an important role in macrophage infiltration in the context of hepatocellular carcinoma. The therapeutic effects of CSF-1R blockade in hepatocellular carcinoma remain unclear. In this study, we found that CSF-1R blockade by PLX3397, a competitive inhibitor with high specificity for CSF-1R tyrosine kinase, significantly delayed tumor growth in mouse models. PLX3397 inhibited the proliferation of macrophages in vitro, but intratumoral macrophage infiltration was not decreased by PLX3397 in vivo Gene expression profiling of tumor-associated macrophages (TAM) showed that TAMs from the PLX3397-treated tumors were polarized toward an M1-like phenotype compared with those from vehicle-treated tumors. In addition, PLX3397 treatment increased CD8(+) T-cell infiltration, whereas CD4(+) T-cell infiltration was decreased. Further study revealed that tumor cell-derived CSF-2 protected TAMs from being depleted by PLX3397. In conclusion, CSF-1R blockade delayed tumor growth by shifting the polarization rather than the depletion of TAMs. CSF-1R blockade warrants further investigation in the treatment of hepatocellular carcinoma. Mol Cancer Ther; 16(8); 1544-54. ©2017 AACR. ©2017 American Association for Cancer Research.

  2. Histamine 1 Receptor Blockade Enhances Eosinophil-Mediated Clearance of Adult Filarial Worms (United States)

    Fox, Ellen Mueller; Morris, Christopher P.; Hübner, Marc P.; Mitre, Edward


    Filariae are tissue-invasive nematodes that cause diseases such as elephantiasis and river blindness. The goal of this study was to characterize the role of histamine during Litomosoides sigmodontis infection of BALB/c mice, a murine model of filariasis. Time course studies demonstrated that while expression of histidine decarboxylase mRNA increases throughout 12 weeks of infection, serum levels of histamine exhibit two peaks—one 30 minutes after primary infection and one 8 weeks later. Interestingly, mice treated with fexofenadine, a histamine receptor 1 inhibitor, demonstrated significantly reduced worm burden in infected mice compared to untreated infected controls. Although fexofenadine-treated mice had decreased antigen-specific IgE levels as well as lower splenocyte IL-5 and IFNγ production, they exhibited a greater than fourfold rise in eosinophil numbers at the tissue site where adult L. sigmodontis worms reside. Fexofenadine-mediated clearance of L. sigmodontis worms was dependent on host eosinophils, as fexofenadine did not decrease worm burdens in eosinophil-deficient dblGATA mice. These findings suggest that histamine release induced by tissue invasive helminths may aid parasite survival by diminishing eosinophilic responses. Further, these results raise the possibility that combining H1 receptor inhibitors with current anthelmintics may improve treatment efficacy for filariae and other tissue-invasive helminths. PMID:26204515

  3. Angiotensin AT1 Receptor-associated protein Arap1 in the Kidney Vasculature is Suppressed by Angiotensin II

    DEFF Research Database (Denmark)

    Doblinger, Elisabeth; Hoecherl, Klaus; Mederle, Katharina


    Arap1 is a protein that interacts with angiotensin II type 1 (AT1) receptors and facilitates increased AT1 receptor surface expression in vitro. In the present study we assessed the tissue localization and regulation of Arap1 in vivo. Arap1 was found in various mouse organs with highest expression...... in the heart, kidney, aorta, and adrenal gland. Renal Arap1 protein was restricted to the vasculature and to glomerular mesangial cells and was absent from tubular epithelia. A similar localization was found in human kidneys. To test the hypothesis that angiotensin II may control renal Arap1 expression, mice...

  4. Differential mechanisms of activation of the Ang peptide receptors AT1, AT2, and MAS: using in silico techniques to differentiate the three receptors.

    Directory of Open Access Journals (Sweden)

    Jeremy W Prokop

    Full Text Available The renin-angiotensin system is involved in multiple conditions ranging from cardiovascular disorders to cancer. Components of the pathway, including ACE, renin and angiotensin receptors are targets for disease treatment. This study addresses three receptors of the pathway: AT1, AT2, and MAS and how the receptors are similar and differ in activation by angiotensin peptides. Combining biochemical and amino acid variation data with multiple species sequence alignments, structural models, and docking site predictions allows for visualization of how angiotensin peptides may bind and activate the receptors; allowing identification of conserved and variant mechanisms in the receptors. MAS differs from AT1 favoring Ang-(1-7 and not Ang II binding, while AT2 recently has been suggested to preferentially bind Ang III. A new model of Ang peptide binding to AT1 and AT2 is proposed that correlates data from site directed mutagenesis and photolabled experiments that were previously considered conflicting. Ang II binds AT1 and AT2 through a conserved initial binding mode involving amino acids 111 (consensus 325 of AT1 (Asn interacting with Tyr (4 of Ang II and 199 and 256 (consensus 512 and 621, a Lys and His respectively interacting with Phe (8 of Ang II. In MAS these sites are not conserved, leading to differential binding and activation by Ang-(1-7. In both AT1 and AT2, the Ang II peptide may internalize through Phe (8 of Ang II propagating through the receptors' conserved aromatic amino acids to the final photolabled positioning relative to either AT1 (amino acid 294, Asn, consensus 725 or AT2 (138, Leu, consensus 336. Understanding receptor activation provides valuable information for drug design and identification of other receptors that can potentially bind Ang peptides.

  5. Differential effects of dopamine and opioid receptor blockade on motivated Coca-Cola drinking behavior and associated changes in brain, skin and muscle temperatures. (United States)

    Kiyatkin, E A


    Although pharmacological blockade of both dopamine (DA) and opiate receptors has an inhibiting effect on appetitive motivated behaviors, it is still unclear which physiological mechanisms affected by these treatments underlie the behavioral deficit. To clarify this issue, we examined how pharmacological blockade of either DA (SCH23390+eticlopride at 0.2 mg/kg each) or opioid receptors (naloxone 1 mg/kg) affects motor activity and temperature fluctuations in the nucleus accumbens (NAcc), temporal muscle, and facial skin associated with motivated Coca-Cola drinking behavior in rats. In drug-free conditions, presentation of a cup containing 5 ml of Coca-Cola induced locomotor activation and rapid NAcc temperature increases, which both transiently decreased during drinking, and phasically increased again after the cup was emptied. Muscle temperatures followed this pattern, but increases were weaker and more delayed than those in the NAcc. Skin temperature rapidly dropped after cup presentation, remained at low levels during consumption, and slowly restored during post-consumption behavioral activation. By itself, DA receptor blockade induced robust decrease in spontaneous locomotion, moderate increases in brain and muscle temperatures, and a relative increase in skin temperatures, suggesting metabolic activation coupled with adynamia. Following this treatment (approximately 180 min), motor activation to cup presentation and Coca-Cola consumption were absent, but rats showed NAcc and muscle temperature increases following cup presentation comparable to control. Therefore, DA receptor blockade does not affect significantly central and peripheral autonomic responses to appetitive stimuli, but eliminates their behavior-activating effects, thus disrupting appetitive behavior and blocking consumption. Naloxone alone slightly decreased brain and muscle temperatures and increased skin temperatures, pointing at the enhanced heat loss and possible minor inhibition of basal

  6. Due to interleukin-6 type cytokine redundancy only glycoprotein 130 receptor blockade efficiently inhibits myeloma growth (United States)

    Burger, Renate; Günther, Andreas; Klausz, Katja; Staudinger, Matthias; Peipp, Matthias; Penas, Eva Maria Murga; Rose-John, Stefan; Wijdenes, John; Gramatzki, Martin


    Interleukin-6 has an important role in the pathophysiology of multiple myeloma where it supports the growth and survival of the malignant plasma cells in the bone marrow. It belongs to a family of cytokines which use the glycoprotein 130 chain for signal transduction, such as oncostatin M or leukemia inhibitory factor. Targeting interleukin-6 in plasma cell diseases is currently evaluated in clinical trials with monoclonal antibodies. Here, efforts were made to elucidate the contribution of interleukin-6 and glycoprotein 130 signaling in malignant plasma cell growth in vivo. In the xenograft severe combined immune deficiency model employing our interleukin-6-dependent plasma cell line INA-6, the lack of human interleukin-6 induced autocrine interleukin-6 production and a proliferative response to other cytokines of the glycoprotein 130 family. Herein, mice were treated with monoclonal antibodies against human interleukin-6 (elsilimomab/B-E8), the interleukin-6 receptor (B-R6), and with an antibody blocking glycoprotein 130 (B-R3). While treatment of mice with interleukin-6 and interleukin-6 receptor antibodies resulted in a modest delay in tumor growth, the development of plasmacytomas was completely prevented with the anti-glycoprotein 130 antibody. Importantly, complete inhibition was also achieved using F(ab’)2-fragments of monoclonal antibody B-R3. Tumors harbor activated signal transducer and activator of transcription 3, and in vitro, the antibody inhibited leukemia inhibitory factor stimulated signal transducer and activator of transcription 3 phosphorylation and cell growth, while being less effective against interleukin-6. In conclusion, the growth of INA-6 plasmacytomas in vivo under interleukin-6 withdrawal remains strictly dependent on glycoprotein 130, and other glycoprotein 130 cytokines may substitute for interleukin-6. Antibodies against glycoprotein 130 are able to overcome this redundancy and should be explored for a possible therapeutic window

  7. Angiotensin-2 receptors (AT1-R and AT2-R), new prognostic factors for renal clear-cell carcinoma? (United States)

    Dolley-Hitze, T; Jouan, F; Martin, B; Mottier, S; Edeline, J; Moranne, O; Le Pogamp, P; Belaud-Rotureau, M-A; Patard, J-J; Rioux-Leclercq, N; Vigneau, C


    The growth factor Angiotensin-2 signals through Angiotensin receptor type 1 (AT1-R) in a broad range of cell types and tumours and through the type-2 receptor (AT2-R) in a more restricted group of cell types. Although numerous forms of cancer have been shown to overexpress AT1-R, expression of AT1-R and AT2-R by human renal clear-cell carcinoma (RCCC) is not well understood. In this study, the expression of both angiotensin receptors was quantified in a retrospective series of RCCC and correlated with prognostic factors. Angiotensin receptor type 1 and AT2-R expressions were quantified on tumour tissues by immunohistochemistry (IHC), western blot and quantitative reverse transcriptase PCR (qRT-PCR). IHC results were correlated to Fuhrman's grade and patient progression-free survival (PFS). A total of 84 RCCC were analysed. By IHC, AT1-R and AT2-R were expressed to a greater level in high-grade tumours (AT1-R: PR: PR or AT2-R expression (P=0.001). By multivariate analysis, only AT2-R expression correlated with PFS (HR 1.021, P=0.006) and cancer stage (PR and AT1-R were also found to be overexpressed in higher Fuhrman's grade (PR but not AT2-R mRNA were downregulated (P=0.001 and P=0.118, respectively). Our results show that AT1-R and AT2-R proteins are overexpressed in the most aggressive forms of RCCC and that AT2-R expression correlates with PFS. AT1-R or AT2-R blockage could, therefore, offer novel directions for anti-RCCC therapy.

  8. Neurohumoral blockade in CHF management

    Directory of Open Access Journals (Sweden)

    Roland Willenbrock


    Full Text Available Is heart failure an endocrine disease? Historically, congestive heart failure (CHF has often been regarded as a mechanical and haemodynamic condition. However, there is now strong evidence that the activation of neuroendocrine systems, like the renin-angiotensin-aldosterone system (RAAS and sympathetic nervous system, as well as the activation of natriuretic peptides, endothelin and vasopressin, play key roles in the progression of CHF. In this context, agents targeting neurohormones offer a highly rational approach to CHF management, with ACE inhibitors, aldosterone antagonists and beta-adrenergic blockade improving the prognosis for many patients. Although relevant improvements in clinical status and survival can be achieved with these drug classes, mortality rates for patients with CHF are still very high. Moreover, most patients do not receive these proven life-prolonging drugs, partially due to fear of adverse events, such as hypotension (with ACE inhibitors, gynaecomastia (with spironolactone and fatigue (with beta-blockers.New agents that combine efficacy with better tolerability are therefore needed. The angiotensin II type 1 (AT1-receptor blockers have the potential to fulfil both these requirements, by blocking the deleterious cardiovascular and haemodynamic effects of angiotensin II while offering placebo-like tolerability. As shown with candesartan, AT1-receptor blockers also modulate the levels of other neurohormones, including aldosterone and atrial natriuretic peptide (ANP. Combined with its tight, long-lasting binding to AT1-receptors, this characteristic gives candesartan the potential for complete blockade of the RAAS-neurohormonal axis, along with the great potential to improve clinical outcomes.

  9. Regional variation in aortic AT1b receptor mRNA abundance is associated with contractility but unrelated to atherosclerosis and aortic aneurysms.

    Directory of Open Access Journals (Sweden)

    Aruna Poduri

    Full Text Available Angiotensin II (AngII, the main bioactive peptide of the renin angiotensin system, exerts most of its biological actions through stimulation of AngII type 1 (AT1 receptors. This receptor is expressed as 2 structurally similar subtypes in rodents, termed AT1a and AT1b. Although AT1a receptors have been studied comprehensively, roles of AT1b receptors in the aorta have not been defined.We initially compared the regional distribution of AT1b receptor mRNA with AT1a receptor mRNA in the aorta. mRNA abundance of both subtypes increased from the proximal to the distal aorta, with the greatest abundance in the infra-renal region. Corresponding to the high mRNA abundance for both receptors, only aortic rings from the infra-renal aorta contracted in response to AngII stimulation. Despite the presence of both receptor transcripts, deletion of AT1b receptors, but not AT1a receptors, diminished AngII-induced contractility. To determine whether absence of AT1b receptors influenced aortic pathologies, we bred AT1b receptor deficient mice into an LDL receptor deficient background. Mice were fed a diet enriched in saturated fat and infused with AngII (1,000 ng/kg/min. Parameters that could influence development of aortic pathologies, including systolic blood pressure and plasma cholesterol concentrations, were not impacted by AT1b receptor deficiency. Absence of AT1b receptors also had no effect on size of aortic atherosclerotic lesions and aortic aneurysms in both the ascending and abdominal regions.Regional abundance of AT1b receptor mRNA coincided with AngII-induced regional contractility, but it was not associated with AngII-induced aortic pathologies.

  10. Buspirone Counteracts MK-801-Induced Schizophrenia-Like Phenotypes through Dopamine D3 Receptor Blockade

    Directory of Open Access Journals (Sweden)

    Sebastiano Alfio Torrisi


    Full Text Available Background: Several efforts have been made to develop effective antipsychotic drugs. Currently, available antipsychotics are effective on positive symptoms, less on negative symptoms, but not on cognitive impairment, a clinically relevant dimension of schizophrenia. Drug repurposing offers great advantages over the long-lasting, risky and expensive, de novo drug discovery strategy. To our knowledge, the possible antipsychotic properties of buspirone, an azapirone anxiolytic drug marketed in 1986 as serotonin 5-HT1A receptor (5-HT1AR partial agonist, have not been extensively investigated despite its intriguing pharmacodynamic profile, which includes dopamine D3 (D3R and D4 receptor (D4R antagonist activity. Multiple lines of evidence point to D3R as a valid therapeutic target for the treatment of several neuropsychiatric disorders including schizophrenia. In the present study, we tested the hypothesis that buspirone, behaving as dopamine D3R antagonist, may have antipsychotic-like activity.Materials and Methods: Effects of acute administration of buspirone was assessed on a wide-range of schizophrenia-relevant abnormalities induced by a single administration of the non-competitive NMDAR antagonist MK-801, in both wild-type mice (WT and D3R-null mutant mice (D3R-/-.Results: Buspirone (3 mg⋅kg-1, i.p. was devoid of cataleptogenic activity in itself, but resulted effective in counteracting disruption of prepulse inhibition (PPI, hyperlocomotion and deficit of temporal order recognition memory (TOR induced by MK-801 (0.1 mg⋅kg-1, i.p. in WT mice. Conversely, in D3R-/- mice, buspirone was ineffective in preventing MK-801-induced TOR deficit and it was only partially effective in blocking MK-801-stimulated hyperlocomotion.Conclusion: Taken together, these results indicate, for the first time, that buspirone, might be a potential therapeutic medication for the treatment of schizophrenia. In particular, buspirone, through its D3R antagonist activity

  11. The impact of NMDA receptor blockade on human working memory-related prefrontal function and connectivity. (United States)

    Driesen, Naomi R; McCarthy, Gregory; Bhagwagar, Zubin; Bloch, Michael H; Calhoun, Vincent D; D'Souza, Deepak C; Gueorguieva, Ralitza; He, George; Leung, Hoi-Chung; Ramani, Ramachandran; Anticevic, Alan; Suckow, Raymond F; Morgan, Peter T; Krystal, John H


    Preclinical research suggests that N-methyl-D-aspartate glutamate receptors (NMDA-Rs) have a crucial role in working memory (WM). In this study, we investigated the role of NMDA-Rs in the brain activation and connectivity that subserve WM. Because of its importance in WM, the lateral prefrontal cortex, particularly the dorsolateral prefrontal cortex and its connections, were the focus of analyses. Healthy participants (n=22) participated in a single functional magnetic resonance imaging session. They received saline and then the NMDA-R antagonist ketamine while performing a spatial WM task. Time-course analysis was used to compare lateral prefrontal activation during saline and ketamine administration. Seed-based functional connectivity analysis was used to compare dorsolateral prefrontal connectivity during the two conditions and global-based connectivity was used to test for laterality in these effects. Ketamine reduced accuracy on the spatial WM task and brain activation during the encoding and early maintenance (EEM) period of task trials. Decrements in task-related activation during EEM were related to performance deficits. Ketamine reduced connectivity in the DPFC network bilaterally, and region-specific reductions in connectivity were related to performance. These results support the hypothesis that NMDA-Rs are critical for WM. The knowledge gained may be helpful in understanding disorders that might involve glutamatergic deficits such as schizophrenia and developing better treatments.

  12. The effect of hippocampal NMDA receptor blockade by MK-801 on cued fear extinction. (United States)

    Zhang, Bo; Li, Chuan-Yu; Wang, Xiu-Song


    Extinction of conditioned fear has been suggested to be a new form of learning instead of erasure of what was originally learned, and the process is NMDA (N-methyl d-aspartate) receptor (NMDAR) dependent. Most of studies have so far revealed the important roles of NMDARs in the amygdala and medial prefrontal cortex (mPFC) in cued fear extinction. Although the ventral hippocampus has intimately reciprocal connections with the amygdala and mPFC, the role of its NMDARs in cued fear extinction remains unclear. The present experiment explored the issue by bilateral pre-extinction microinjection of the noncompetitive NMDAR antagonist MK-801 into the ventral hippocampus. Four groups of rats were given habituation, tone cued fear conditioning, fear extinction training and extinction test. Prior to extinction training, rats received bilateral infusions of either MK-801 (1.5, 3, or 6μg/0.5μl) or saline. Our results showed that MK-801 reduced freezing on the first trial of extinction training with no impact on within-session acquisition of extinction, and that the lower doses of MK-801 resulted in increased freezing on the extinction retrieval test. These findings suggest that ventral hippocampal NMDARs are necessary for the consolidation of tone cued fear extinction. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Hippocampal oscillations in the rodent model of schizophrenia induced by amygdala GABA receptor blockade

    Directory of Open Access Journals (Sweden)

    Tope eLanre-Amos


    Full Text Available Brain oscillations are critical for cognitive processes, and their alterations in schizophrenia have been proposed to contribute to cognitive impairments. Network oscillations rely upon GABAergic interneurons, which also show characteristic changes in schizophrenia. The aim of this study was to examine the capability of hippocampal networks to generate oscillations in a rat model previously shown to reproduce the stereotypic structural alterations of the hippocampal interneuron circuit seen in schizophrenic patients. This model uses injection of GABA-A receptor antagonist picrotoxin into the basolateral amygdala which causes cell-type specific disruption of interneuron signaling in the hippocampus. We found that after such treatment, hippocampal theta rhythm was still present during REM sleep, locomotion, and exploration of novel environment and could be elicited under urethane anesthesia. Subtle changes in theta and gamma parameters were observed in both preparations; specifically in the stimulus intensity—theta frequency relationship under urethane and in divergent reactions of oscillations at the two major theta dipoles in freely moving rats. Thus, theta power in the CA1 region was generally enhanced as compared with deep theta dipole which decreased or did not change. The results indicate that pathologic reorganization of interneurons that follows the over-activation of the amygdala-hippocampal pathway, as shown for this model of schizophrenia, does not lead to destruction of the oscillatory circuit but changes the normal balance of rhythmic activity in its various compartments.

  14. Enhanced water and salt intake in transgenic mice with brain-restricted overexpression of angiotensin (AT1) receptors. (United States)

    Lazartigues, Eric; Sinnayah, Puspha; Augoyard, Ginette; Gharib, Claude; Johnson, Alan Kim; Davisson, Robin L


    To address the relative contribution of central and peripheral angiotensin II (ANG II) type 1A receptors (AT(1A)) to blood pressure and volume homeostasis, we generated a transgenic mouse model [neuron-specific enolase (NSE)-AT(1A)] with brain-restricted overexpression of AT(1A) receptors. These mice are normotensive at baseline but have dramatically enhanced pressor and bradycardic responses to intracerebroventricular ANG II or activation of endogenous ANG II production. Here our goal was to examine the water and sodium intake in this model under basal conditions and in response to increased ANG II levels. Baseline water and NaCl (0.3 M) intakes were significantly elevated in NSE-AT(1A) compared with nontransgenic littermates, and bolus intracerebroventricular injections of ANG II (200 ng in 200 nl) caused further enhanced water intake in NSE-AT(1A). Activation of endogenous ANG II production by sodium depletion (10 days low-sodium diet followed by furosemide, 1 mg sc) enhanced NaCl intake in NSE-AT(1A) mice compared with wild types. Fos immunohistochemistry, used to assess neuronal activation, demonstrated sodium depletion-enhanced activity in the anteroventral third ventricle region of the brain in NSE-AT(1A) mice compared with control animals. The results show that brain-selective overexpression of AT(1A) receptors results in enhanced salt appetite and altered water intake. This model provides a new tool for studying the mechanisms of brain AT(1A)-dependent water and salt consumption.

  15. Calcium dependency of the AT1-receptor mediated effects in the rat portal vein: influence of calcium antagonists

    NARCIS (Netherlands)

    Zhang, J. S.; van Meel, J. C.; Pfaffendorf, M.; Zhang, J.; van Zwieten, P. A.


    The calcium dependency of AT1-receptor mediated contractions was studied in isolated rat portal vein preparations. The spontaneous phasic contractile force of the rat portal vein was increased (ED50 = 1.76 mmol/l) and the frequency of contractions decreased by raising the extracellular calcium

  16. Renal proximal tubule angiotensin AT1A receptors regulate blood pressure. (United States)

    Li, Huiping; Weatherford, Eric T; Davis, Deborah R; Keen, Henry L; Grobe, Justin L; Daugherty, Alan; Cassis, Lisa A; Allen, Andrew M; Sigmund, Curt D


    All components of the renin angiotensin system necessary for ANG II generation and action have been reported to be present in renal proximal convoluted tubules. Given the close relationship between renal sodium handling and blood pressure regulation, we hypothesized that modulating the action of ANG II specifically in the renal proximal tubules would alter the chronic level of blood pressure. To test this, we used a proximal tubule-specific, androgen-dependent, promoter construct (KAP2) to generate mice with either overexpression of a constitutively active angiotensin type 1A receptor transgene or depletion of endogenous angiotensin type 1A receptors. Androgen administration to female transgenic mice caused a robust induction of the transgene in the kidney and increased baseline blood pressure. In the receptor-depleted mice, androgen administration to females resulted in a Cre recombinase-mediated deletion of angiotensin type 1A receptors in the proximal tubule and reduced blood pressure. In contrast to the changes observed at baseline, there was no difference in the blood pressure response to a pressor dose of ANG II in either experimental model. These data, from two separate mouse models, provide evidence that ANG II signaling via the type 1A receptor in the renal proximal tubule is a regulator of systemic blood pressure under baseline conditions.

  17. Effect of oxytocin receptor blockade on appetite for sugar is modified by social context. (United States)

    Olszewski, Pawel K; Allen, Kerry; Levine, Allen S


    Research on oxytocin (OT) has yielded two seemingly unrelated sets of discoveries: OT has prosocial effects, and it elicits termination of feeding, especially of food rich in carbohydrates. Here we investigated whether OT's involvement in food intake is affected by the social context in mice, with particular focus on the role of dominance. We used two approaches: injections and gene expression analysis. We housed two males per cage and determined a dominant one. Then we injected a blood-brain barrier penetrant OT receptor antagonist L-368,899 in either dominant or subordinate animals and gave them 10-min access to a sucrose solution in the apparatus in which social exposure was modified and it ranged from none to unrestricted contact. L-368,899 increased the amount of consumed sugar in dominant mice regardless of whether these animals had access to sucrose in the non-social or social contexts (olfactory-derived or partial social exposure). The antagonist also increased the proportion of time that dominant mice spent drinking the sweet solution in the paradigm in which both mice had to share a single source of sucrose. L-368,899-treated subordinate mice consumed more sucrose solution than saline controls only when the environment in which sugar was presented was devoid of social cues related to the dominant animal. Finally, we investigated whether hypothalamic OT gene expression differs between dominant and subordinate mice consuming sugar and found OT mRNA levels to be higher in dominant mice. We conclude that social context and dominance affect OT's effect on appetite for sucrose. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Blockade of muscarinic receptors impairs the retrieval of well-trained memory

    Directory of Open Access Journals (Sweden)

    Shogo eSoma


    Full Text Available Acetylcholine (ACh is known to play an important role in memory functions, and its deficit has been proposed to cause the cognitive decline associated with advanced age and Alzheimer’s disease (the cholinergic hypothesis. Although many studies have tested the cholinergic hypothesis for recently acquired memory, only a few have investigated the role of ACh in the retrieval process of well-trained cognitive memory, which describes the memory established from repetition and daily routine. To examine this point, we trained rats to perform a two-alternative forced-choice visual detection task. Each trial was started by having the rats pull upward a central-lever, which triggered the presentation of a visual stimulus to the right or left side of the display monitor, and then pulling upward a stimulus-relevant choice-lever located on both sides. Rats learned the task within 10 days, and the task training was continued for a month. Task performance was measured with or without systemic administration of a muscarinic ACh receptor (mAChR antagonist, scopolamine (SCOP, prior to the test. After 30 min of SCOP administration, rats stopped manipulating any lever even though they explored the lever and surrounding environment, suggesting a loss of the task-related associative memory. Three hours later, rats were recovered to complete the trial, but the rats selected the levers irrespective of the visual stimulus, suggesting they remembered a series of lever-manipulations in association with a reward, but not association between the reward and visual stimulation. Furthermore, an m1-AChR, but not nicotinic AChR antagonist caused a similar deficit in the task execution. SCOP neither interfered with locomotor activity nor drinking behavior, while it influenced anxiety. These results suggest that the activation of mAChRs at basal ACh levels is essential for the recall of well-trained cognitive memory.

  19. Androgen receptor splice variants circumvent AR blockade by microtubule-targeting agents (United States)

    Zhang, Guanyi; Liu, Xichun; Li, Jianzhuo; Ledet, Elisa; Alvarez, Xavier; Qi, Yanfeng; Fu, Xueqi; Sartor, Oliver; Dong, Yan; Zhang, Haitao


    Docetaxel-based chemotherapy is established as a first-line treatment and standard of care for patients with metastatic castration-resistant prostate cancer. However, half of the patients do not respond to treatment and those do respond eventually become refractory. A better understanding of the resistance mechanisms to taxane chemotherapy is both urgent and clinical significant, as taxanes (docetaxel and cabazitaxel) are being used in various clinical settings. Sustained signaling through the androgen receptor (AR) has been established as a hallmark of CRPC. Recently, splicing variants of AR (AR-Vs) that lack the ligand-binding domain (LBD) have been identified. These variants are constitutively active and drive prostate cancer growth in a castration-resistant manner. In taxane-resistant cell lines, we found the expression of a major variant, AR-V7, was upregulated. Furthermore, ectopic expression of two clinically relevant AR-Vs (AR-V7 and ARV567es), but not the full-length AR (AR-FL), reduced the sensitivities to taxanes in LNCaP cells. Treatment with taxanes inhibited the transcriptional activity of AR-FL, but not those of AR-Vs. This could be explained, at least in part, due to the inability of taxanes to block the nuclear translocation of AR-Vs. Through a series of deletion constructs, the microtubule-binding activity was mapped to the LBD of AR. Finally, taxane-induced cytoplasm sequestration of AR-FL was alleviated when AR-Vs were present. These findings provide evidence that constitutively active AR-Vs maintain the AR signaling axis by evading the inhibitory effects of microtubule-targeting agents, suggesting that these AR-Vs play a role in resistance to taxane chemotherapy. PMID:26160840

  20. Incorporation of Immune Checkpoint Blockade into Chimeric Antigen Receptor T Cells (CAR-Ts: Combination or Built-In CAR-T

    Directory of Open Access Journals (Sweden)

    Dok Hyun Yoon


    Full Text Available Chimeric antigen receptor (CAR T cell therapy represents the first U.S. Food and Drug Administration approved gene therapy and these engineered cells function with unprecedented efficacy in the treatment of refractory CD19 positive hematologic malignancies. CAR translation to solid tumors is also being actively investigated; however, efficacy to date has been variable due to tumor-evolved mechanisms that inhibit local immune cell activity. To bolster the potency of CAR-T cells, modulation of the immunosuppressive tumor microenvironment with immune-checkpoint blockade is a promising strategy. The impact of this approach on hematological malignancies is in its infancy, and in this review we discuss CAR-T cells and their synergy with immune-checkpoint blockade.

  1. P2X7 receptor blockade protects against cisplatin-induced nephrotoxicity in mice by decreasing the activities of inflammasome components, oxidative stress and caspase-3

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    Zhang, Yuanyuan; Yuan, Fahuan; Cao, Xuejiao [Department of Nephrology, Xinqiao Hospital, PLA, Third Military Medical University, Chongqing 400037 (China); Zhai, Zhifang [Department of Dermatology, Southwest Hospital, Third Military Medical University, Chongqing 400038 (China); Gang Huang [Department of Medical Genetics, Third Military Medical University, Chongqing 430038 (China); Du, Xiang; Wang, Yiqin; Zhang, Jingbo; Huang, Yunjian; Zhao, Jinghong [Department of Nephrology, Xinqiao Hospital, PLA, Third Military Medical University, Chongqing 400037 (China); Hou, Weiping, E-mail: [Department of Nephrology, Xinqiao Hospital, PLA, Third Military Medical University, Chongqing 400037 (China)


    Nephrotoxicity is a common complication of cisplatin chemotherapy and thus limits the use of cisplatin in clinic. The purinergic 2X7 receptor (P2X7R) plays important roles in inflammation and apoptosis in some inflammatory diseases; however, its roles in cisplatin-induced nephrotoxicity remain unclear. In this study, we first assessed the expression of P2X7R in cisplatin-induced nephrotoxicity in C57BL/6 mice, and then we investigated the changes of renal function, histological injury, inflammatory response, and apoptosis in renal tissues after P2X7R blockade in vivo using an antagonist A-438079. Moreover, we measured the changes of nod-like receptor family, pyrin domain containing proteins (NLRP3) inflammasome components, oxidative stress, and proapoptotic genes in renal tissues in cisplatin-induced nephrotoxicity after treatment with A-438079. We found that the expression of P2X7R was significantly upregulated in the renal tubular epithelial cells in cisplatin-induced nephrotoxicity compared with that of the normal control group. Furthermore, pretreatment with A-438079 markedly attenuated the cisplatin-induced renal injury while lightening the histological damage, inflammatory response and apoptosis in renal tissue, and improved the renal function. These effects were associated with the significantly reduced levels of NLRP3 inflammasome components, oxidative stress, p53 and caspase-3 in renal tissues in cisplatin-induced nephrotoxicity. In conclusions, our studies suggest that the upregulated activity of P2X7R might play important roles in the development of cisplatin-induced nephrotoxicity, and P2X7R blockade might become an effective therapeutic strategy for this disease. - Highlights: • The P2X7R expression was markedly upregulated in cisplatin-induced nephrotoxicity. • P2X7R blockade significantly attenuated the cisplatin-induced renal injury. • P2X7R blockade reduced activities of NLRP3 inflammasome components in renal tissue. • P2X7R blockade

  2. Angiotensin II AT1 receptor blocker candesartan prevents the fast up-regulation of cerebrocortical benzodiazepine-1 receptors induced by acute inflammatory and restraint stress (United States)

    Sánchez-Lemus, Enrique; Honda, Masaru; Saavedra, Juan M.


    Centrally acting Angiotensin II AT1 receptor blockers (ARBs) protect from stress-induced disorders and decrease anxiety in a model of inflammatory stress, the systemic injection of bacterial endotoxin lipopolysaccharide (LPS). In order to better understand the anxiolytic effect of ARBs, we treated rats with LPS (50 µg/kg) with or without three days of pretreatment with the ARB candesartan (1 mg/kg/day), and studied cortical benzodiazepine (BZ) and corticotrophin-releasing factor (CRF) receptors. We compared the cortical BZ and CRF receptors expression pattern induced by LPS with that produced in restraint stress. Inflammation stress produced a generalized increase in cortical BZ1 receptors and reduced mRNA expression of the GABAA receptor γ2 subunit in cingulate cortex; changes were prevented by candesartan pretreatment. Moreover, restraint stress produced similar increases in cortical BZ1 receptor binding, and candesartan prevented these changes. Treatment with candesartan alone increased cortical BZ1 binding, and decreased γ2 subunit mRNA expression in the cingulate cortex. Conversely, we did not find changes in CRF1 receptor expression in any of the cortical areas studied, either after inflammation or restraint stress. Cortical CRF2 receptor binding was undetectable, but CRF2 mRNA expression was decreased by inflammation stress, a change prevented by candesartan. We conclude that stress promotes rapid and widespread changes in cortical BZ1 receptor expression; and that the stress-induced BZ1 receptor expression is under the control of AT1 receptor activity. The results suggest that the anti-anxiety effect of ARBs may be associated with their capacity to regulate stress-induced alterations in cortical BZ1 receptors. PMID:22503782

  3. Hypoxia and high glucose upregulate AT1 receptor expression and potentiate ANG II-induced proliferation in VSM cells. (United States)

    Sodhi, Chhinder P; Kanwar, Yashpal S; Sahai, Atul


    We examined the effect of hypoxia and high glucose (HG) on ANG II type 1 (AT(1)) receptor expression and proliferation in cultured vascular smooth muscle (VSM) cells. Exposure of quiescent cells to hypoxia in a serum-free DME-Ham's F-12 medium for 6-24 h induced a progressive increase in AT(1) mRNA expression. Exposure of cells to 24 h of hypoxia also resulted in a significant increase in ANG II receptor binding as assessed with (125)I-labeled ANG II. Treatment with ANG II (1 microM) for 24 h under normoxic conditions caused an approximately 1.5-fold increase in both DNA synthesis and cell number, which was enhanced to approximately 3.0-fold under hypoxic conditions. An AT(1) receptor antagonist (losartan, 10 microM) blocked the ANG II-induced increase in DNA synthesis under both normoxic and hypoxic conditions. Incubations in HG medium (25 mM) for 12-24 h under normoxic conditions induced an approximately 2.5-fold increase in AT(1) mRNA levels, which was markedly enhanced by hypoxia to approximately 5.5-fold at 12 h and approximately 8.5-fold at 24 h. ANG II under HG-normoxic conditions caused a complete downregulation of AT(1) expression, which was prevented by hypoxia. These results demonstrate an upregulation of AT(1) receptor expression by hypoxia and HG in cultured VSM cells and suggest a mechanism for enhanced ANG II-induced VSM cell proliferation and the development of atherosclerosis in diabetes.

  4. Pre- and postsynaptic inhibitory potencies of the angiotensin AT(1) receptor antagonists eprosartan and candesartan

    NARCIS (Netherlands)

    Nap, Alexander; Mathy, Marie-Jeanne; Balt, Jippe C.; Pfaffendorf, Martin; van Zwieten, Pieter A.


    The aim of the present study was to determine the inhibitory potency of two selective angiotensin AT, receptor antagonists, eprosartan and candesartan, at the level of the sympathetic nerve terminal and the vascular smooth muscle. Male New Zealand White rabbits, weighing 2100-2550 g, were used. To

  5. Pilot Study of Endothelin Receptor Blockade in Heart Failure with Diastolic Dysfunction and Pulmonary Hypertension (BADDHY-Trial). (United States)

    Koller, B; Steringer-Mascherbauer, R; Ebner, C H; Weber, Th; Ammer, M; Eichinger, J; Pretsch, I; Herold, M; Schwaiger, J; Ulmer, H; Grander, W


    In this multi-centre, randomised, placebo-controlled pilot trial, we investigated the clinical and haemodynamic effects of the endothelin-receptor blocker Bosentan in patients with heart failure, preserved ejection fraction and pulmonary hypertension (PH-HFpEF). Eligible patients received either 12 weeks of Bosentan therapy, or a placebo drug. Patients were thereafter followed for a further period of 12 weeks without the study medication. At three points during the study (study Commencement, Week 12 and Week 24), a six-minute walk test (6MWT), echocardiographic and laboratory assessments were performed, as well as a quality of life survey. Right heart catheterisation (RHC) was undertaken at commencement only. The study was aborted early, after an interim analysis favoured the placebo. Six-minute walk distance (6MWD) did not change in the Bosentan group (309.7±96.3m (Commencement), 317.0±126.1m (Week 12), 307.0±84.4m (Week 24); p=0.86), but almost reached statistical significance in the placebo group from 328.8±79.6m, to 361.6±98.2m and 384.0±74.9m (Week 24); p=0.075. In the placebo group, estimated systolic pulmonary artery pressure (measured via echocardiography) significantly decreased (from 62.3±16.7mmHg [Commencement], 45.3±13.9mmHg [Week 12], to 44.6±14.5mmHg [Week 24]; p=0.014) as did right atrial pressure (13.1±5.3 [Commencement], 10.0±3.8 [Week 12], to 9.4±3.2 [Week 24]; p=0.046). Despite this study's limited sample size and premature cessation, it nevertheless suggests that endothelin receptor blockade in patients with PH-HFpEF may have no beneficial effects and could even be detrimental in comparison to a placebo. Copyright © 2016 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

  6. Ontogeny and regulation of the AT1 and AT2 receptors in the ovine fetal adrenal gland. (United States)

    Wintour, E M; Moritz, K; Butkus, A; Baird, R; Albiston, A; Tenis, N


    The expression and regulation of the receptors for angiotensin II (both AT1 and AT2) were examined in the ovine fetal adrenal gland by RNase protection assay (RPA), in situ hybridisation histochemistry, immunohistochemistry and Western blotting. Both mRNA and protein for the AT1 receptor were present in the zona glomerulosa and zona fasciculata of the cortex, but not in the medulla, from as early as these zonas were distinguishable (60 days of gestation; term is 145-150 days), and even present in the steroidogenic cells of the unzoned gland at 40 days. The mRNA for the AT2 receptor was present in the same locations (but never in the medulla) from 40-130 days, and declined to extremely low levels after 140 days. The infusion of ang II, 1 microg/h, for 3 days, at mid-gestation (76 +/- 2 days) caused a significant decrease in mRNA for AT1 but no change in AT2 levels. Thus, the biologically active receptor (in terms of aldosterone stimulation) is present in the ovine fetal adrenal from very early in development, and can be down-regulated by mid-gestation.

  7. Edaravone inhibits pressure overload-induced cardiac fibrosis and dysfunction by reducing expression of angiotensin II AT1 receptor. (United States)

    Zhang, Wei-Wei; Bai, Feng; Wang, Jin; Zheng, Rong-Hua; Yang, Li-Wang; James, Erskine A; Zhao, Zhi-Qing


    Angiotensin II (Ang II) is known to be involved in the progression of ventricular dysfunction and heart failure by eliciting cardiac fibrosis. The purpose of this study was to demonstrate whether treatment with an antioxidant compound, edaravone, reduces cardiac fibrosis and improves ventricular function by inhibiting Ang II AT1 receptor. The study was conducted in a rat model of transverse aortic constriction (TAC). In control, rats were subjected to 8 weeks of TAC. In treated rats, edaravone (10 mg/kg/day) or Ang II AT1 receptor blocker, telmisartan (10 mg/kg/day) was administered by intraperitoneal injection or gastric gavage, respectively, during TAC. Relative to the animals with TAC, edaravone reduced myocardial malonaldehyde level and increased superoxide dismutase activity. Protein level of the AT1 receptor was reduced and the AT2 receptor was upregulated, as evidenced by the reduced ratio of AT1 over AT2 receptor (0.57±0.2 vs 3.16±0.39, preceptor in the myocardium. Furthermore, the protein level of angiotensin converting enzyme 2 was upregulated. In coincidence with these changes, edaravone significantly decreased the populations of macrophages and myofibroblasts in the myocardium, which were accompanied by reduced levels of transforming growth factor beta 1 and Smad2/3. Collagen I synthesis was inhibited and collagen-rich fibrosis was attenuated. Relative to the TAC group, cardiac systolic function was preserved, as shown by increased left ventricular systolic pressure (204±51 vs 110±19 mmHg, preceptor-mediated signaling pathways. These data indicate that edaravone might be selected in combination with other existing drugs in preventing progression of cardiac dysfunction in heart failure.

  8. Angiotensin AT1 receptors modulate the anxiogenic effects of angiotensin (5-8) injected into the rat ventrolateral periaqueductal gray. (United States)

    Genaro, Karina; Fabris, Débora; Fachim, Helene A; Prado, Wiliam A


    Losartan and PD 123,319 are non-peptide angiotensin (Ang) receptor antagonists for the AT1 and AT2 subtypes of Ang II receptors, respectively. The tetrapeptide Ang (5-8) is the smallest Ang-peptide that elicits anxiogenic effects on unconditioned and conditioned experimental models upon injection into the ventrolateral column of the periaqueductal gray (vlPAG), and Ang (5-8) can be synthesized (from Ang II or Ang III) and inactivated in this mesencephalic structure. The vlPAG is also known to play a central role in mechanisms of fear and anxiety. We therefore utilized male Wistar rats to examine the effects of losartan and PD 123,319 injections, selective antagonists of the AT1 and AT2 receptors, respectively, into the vlPAG in the elevated plus-maze, a classic rat model of anxiety, and against the anxiogenic effect of Ang (5-8) (0.4 nmol/0.25μL) upon injection into the same region. The anxiolytic profile was dependent on the dose of intra-vlPAG losartan, whereas no effects on experimental anxiety were observed in the plus-maze following PD 123,319 injection. The anxiogenic effect of Ang (5-8) injection into the vlPAG remained unchanged in the PD 123,319-pretreated rats, but the effect did not occur in losartan-pretreated rats. The results led us to suggest that the anxiogenic effect of Ang (5-8) injection into the vlPAG may depend on the local activation of AT1, but not AT2 receptors. Activation of AT1 receptors in structures nearby vlPAG may be tonically involved in fear and experimental anxiety. Copyright © 2017. Published by Elsevier Inc.

  9. AT1 receptor blocker losartan protects against mechanical ventilation-induced diaphragmatic dysfunction (United States)

    Kwon, Oh Sung; Smuder, Ashley J.; Wiggs, Michael P.; Hall, Stephanie E.; Sollanek, Kurt J.; Morton, Aaron B.; Talbert, Erin E.; Toklu, Hale Z.; Tumer, Nihal


    Mechanical ventilation is a life-saving intervention for patients in respiratory failure. Unfortunately, prolonged ventilator support results in diaphragmatic atrophy and contractile dysfunction leading to diaphragm weakness, which is predicted to contribute to problems in weaning patients from the ventilator. While it is established that ventilator-induced oxidative stress is required for the development of ventilator-induced diaphragm weakness, the signaling pathway(s) that trigger oxidant production remain unknown. However, recent evidence reveals that increased plasma levels of angiotensin II (ANG II) result in oxidative stress and atrophy in limb skeletal muscles. Using a well-established animal model of mechanical ventilation, we tested the hypothesis that increased circulating levels of ANG II are required for both ventilator-induced diaphragmatic oxidative stress and diaphragm weakness. Cause and effect was determined by administering an angiotensin-converting enzyme inhibitor (enalapril) to prevent ventilator-induced increases in plasma ANG II levels, and the ANG II type 1 receptor antagonist (losartan) was provided to prevent the activation of ANG II type 1 receptors. Enalapril prevented the increase in plasma ANG II levels but did not protect against ventilator-induced diaphragmatic oxidative stress or diaphragm weakness. In contrast, losartan attenuated both ventilator-induced oxidative stress and diaphragm weakness. These findings indicate that circulating ANG II is not essential for the development of ventilator-induced diaphragm weakness but that activation of ANG II type 1 receptors appears to be a requirement for ventilator-induced diaphragm weakness. Importantly, these experiments provide the first evidence that the Food and Drug Administration-approved drug losartan may have clinical benefits to protect against ventilator-induced diaphragm weakness in humans. PMID:26359481

  10. Inhibition of β2-adrenergic receptor reduces triple-negative breast cancer brain metastases: The potential benefit of perioperative β-blockade. (United States)

    Choy, Cecilia; Raytis, John L; Smith, David D; Duenas, Matthew; Neman, Josh; Jandial, Rahul; Lew, Michael W


    In response to recent studies, we investigated an association between perioperative β-blockade and breast cancer metastases. First, a retrospective study examining perioperative β-blocker use and cancer recurrence and metastases was conducted on 1,029 patients who underwent breast cancer surgery at the City of Hope Cancer Center between 2000 and 2010. We followed the clinical study and examined proliferation, migration, and invasion in vitro of primary and brain-metastatic breast cancer cells in response to β2-activation and inhibition. We also investigated in vivo the metastatic potential of propranolol-treated metastatic cells. For stage II breast cancer patients, perioperative β-blockade was associated with decreased cancer recurrence using Cox regression analysis (hazard's ratio =0.51; 95% CI: 0.23-0.97; p=0.041). Triple-negative (TN) brain-metastatic cells were found to have increased β2-adrenergic receptor mRNA and protein expression relative to TN primary cells. In response to β2-adrenergic receptor activation, TN brain-metastatic cells also exhibited increased cell proliferation and migration relative to the control. These effects were abrogated by propranolol. Propranolol decreased β2-adrenergic receptor-activated invasion. In vivo, propranolol treatment of TN brain-metastatic cells decreased establishment of brain metastases. Our results suggest that stress and corresponding β2-activation may promote the establishment of brain metastases of TN breast cancer cells. In addition, our data suggest a benefit to perioperative β-blockade during surgery-induced stress with respect to breast cancer recurrence and metastases.

  11. Evidence for a cyclic AMP-dependent pathway in angiotensin AT1-receptor activation of human omental arteries

    Directory of Open Access Journals (Sweden)

    Hoa Ytterberg


    Full Text Available Enhanced responses to vasoconstriction induced by neuropeptide Y and α2-adrenoceptor agonists have been seen following pharmacological activation of the adenylyl cyclase (AC system. Since preliminary studies revealed only minor responses to angiotensin II (Ang II in human omental arteries, we have investigated whether enhanced activity of AC may unravel further functional Ang II receptors. Human omental arteries were obtained in conjunction with elective gut surgery. After dissection of the vessel, the endothelium was removed by 10 sec of Triton X-100 treatment. Ring segments (1—2 mm long were mounted on a myograph and studied. Ang II produced small contractions, 27±5% relative to the response elicited by 60 mM K+. However, enhanced Ang II (105±10%, p<0.001 responses were seen during AC activation by forskolin (0.1—1 µM. This enhanced contractile response to Ang II was not inhibited by the angiotensin II type 2 (AT2-receptor antagonist PD 123319 (0.1 µM, but was blocked in an insurmountable way by the angiotensin II type 1 (AT1-receptor antagonist candesartan (1 nM and in a surmountable manner by losartan (0.1 µM and irbesartan (0.1 µM. Pertussis toxin (a Gi-protein blocker and the protein kinase C inhibitor, RO31—8220 (0.01, 0.1 and 1 µM, markedly reduced this response, while the protein kinase A inhibitor, H89 (1, 10 µM, had no effect. RT-PCR provided evidence for the presence of mRNA for both AT1- and AT2-receptors. The results suggest that both a cAMP-dependent and a cAMP-independent mechanism are involved in the contractile responses to Ang II in human omental arteries and that both responses are mediated via the AT1-receptor.

  12. Angiotensin Mediated Oxidative Stress and Neuroprotective Potential of Antioxidants and AT1 Receptor Blockers. (United States)

    Prusty, Shakti Ketan; Sahu, Pratap Kumar; Subudhi, Bharat Bhusan


    Oxidative stress in brain underlies the major neurological disorders including Alzheimer's disease (AD) and Parkinson's disease (PD). Peripherally, Angiotensin-II is a major effector of inflammation. Identification of its capacity to access brain during hypertension, as well as location of central renin angiotensin system have led to its recognition as the major effector of oxidative stress in brain. Clinical uses of antioxidants to antagonize this oxidative stress have mostly failed. In this scenario, AT1 blockers have been investigated to prevent neurodegeneration. Although it has shown promise, clinical efficacy is limited to few drugs including telmisartan mainly due to the poor brain availability of others. In this review we aim to analyze the potential of antioxidants to reduce oxidative stress in brain. We have given critical analysis of the approaches for re-purposing of AT1 blockers against oxidative stress induced neurodegeneration. Copyright© Bentham Science Publishers; For any queries, please email at

  13. AT(1) receptor Gαq protein-independent signalling transcriptionally activates only a few genes directly, but robustly potentiates gene regulation from the β2-adrenergic receptor

    DEFF Research Database (Denmark)

    Christensen, Gitte Lund; Knudsen, Steen; Schneider, Mikael


    The angiotensin II type 1 receptor (AT(1)R) is known to signal through heterotrimeric G proteins, and Gαq protein-independent signalling has only recently gained appreciation for profound impact on a diverse range of biological functions. β-Arrestins, among other central mediators of Gαq protein-...

  14. Differential effects of presynaptic versus postsynaptic adenosine A2A receptor blockade on Δ9-tetrahydrocannabinol (THC) self-administration in squirrel monkeys. (United States)

    Justinová, Zuzana; Redhi, Godfrey H; Goldberg, Steven R; Ferré, Sergi


    Different doses of an adenosine A2A receptor antagonist MSX-3 [3,7-dihydro-8-[(1E)-2-(3-ethoxyphenyl)ethenyl]-7 methyl-3-[3-(phosphooxy)propyl-1-(2 propynil)-1H-purine-2,6-dione] were found previously to either decrease or increase self-administration of cannabinoids delta-9-tetrahydrocannabinol (THC) or anandamide in squirrel monkeys. It was hypothesized that the decrease observed with a relatively low dose of MSX-3 was related to blockade of striatal presynaptic A2A receptors that modulate glutamatergic neurotransmission, whereas the increase observed with a higher dose was related to blockade of postsynaptic A2A receptors localized in striatopallidal neurons. This hypothesis was confirmed in the present study by testing the effects of the preferential presynaptic and postsynaptic A2A receptor antagonists SCH-442416 [2-(2-furanyl)-7-[3-(4-methoxyphenyl)propyl]-7H-pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidin-5-amine] and KW-6002 [(E)-1, 3-diethyl-8-(3,4-dimethoxystyryl)-7-methyl-3,7-dihydro-1H-purine-2,6-dione], respectively, in squirrel monkeys trained to intravenously self-administer THC. SCH-442416 produced a significant shift to the right of the THC self-administration dose-response curves, consistent with antagonism of the reinforcing effects of THC. Conversely, KW-6002 produced a significant shift to the left, consistent with potentiation of the reinforcing effects of THC. These results show that selectively blocking presynaptic A2A receptors could provide a new pharmacological approach to the treatment of marijuana dependence and underscore corticostriatal glutamatergic neurotransmission as a possible main mechanism involved in the rewarding effects of THC.

  15. Losartan suppresses the kainate-induced changes of angiotensin AT1 receptor expression in a model of comorbid hypertension and epilepsy. (United States)

    Atanasova, Dimitrinka; Tchekalarova, Jana; Ivanova, Natasha; Nenchovska, Zlatina; Pavlova, Ekaterina; Atanassova, Nina; Lazarov, Nikolai


    Experimental and clinical studies have demonstrated that components of renin-angiotensin system are elevated in the hippocampus in epileptogenic conditions. In the present work, we explored the changes in the expression of angiotensin II receptor, type 1 (AT1 receptor) in limbic structures, as well as the effect of the AT1 receptor antagonist losartan in a model of comorbid hypertension and epilepsy. The expression of AT1 receptors was compared between spontaneously hypertensive rats (SHRs) and Wistar rats by using immunohistochemistry in the kainate (KA) model of temporal lobe epilepsy (TLE). The effect of losartan was studied on AT1 receptor expression in epileptic rats that were treated for a period of 4weeks after status epilepticus. The naive and epileptic SHRs were characterized by stronger protein expression of AT1 receptor than normotensive Wistar rats in the CA1, CA3a, CA3b, CA3c field and the hilus of the dentate gyrus of the dorsal hippocampus but fewer cells were immunostained in the piriform cortex. Increased AT1 immunostaining was observed in the basolateral amygdala of epileptic SHRs but not of epileptic Wistar rats. Losartan exerted stronger and structure-dependent suppression of AT1 receptor expression in SHRs compared to Wistar rats. Our results confirm the important role of AT1 receptor in epilepsy and suggest that the AT1receptor antagonists could be used as a therapeutic strategy for treatment of comorbid hypertension and epilepsy. Copyright © 2017. Published by Elsevier Inc.

  16. AT1 receptor induced alterations in histone H2A reveal novel insights into GPCR control of chromatin remodeling.

    Directory of Open Access Journals (Sweden)

    Rajaganapathi Jagannathan


    Full Text Available Chronic activation of angiotensin II (AngII type 1 receptor (AT(1R, a prototypical G protein-coupled receptor (GPCR induces gene regulatory stress which is responsible for phenotypic modulation of target cells. The AT(1R-selective drugs reverse the gene regulatory stress in various cardiovascular diseases. However, the molecular mechanisms are not clear. We speculate that activation states of AT(1R modify the composition of histone isoforms and post-translational modifications (PTM, thereby alter the structure-function dynamics of chromatin. We combined total histone isolation, FPLC separation, and mass spectrometry techniques to analyze histone H2A in HEK293 cells with and without AT(1R activation. We have identified eight isoforms: H2AA, H2AG, H2AM, H2AO, H2AQ, Q96QV6, H2AC and H2AL. The isoforms, H2AA, H2AC and H2AQ were methylated and H2AC was phosphorylated. The relative abundance of specific H2A isoforms and PTMs were further analyzed in relationship to the activation states of AT(1R by immunochemical studies. Within 2 hr, the isoforms, H2AA/O exchanged with H2AM. The monomethylated H2AC increased rapidly and the phosphorylated H2AC decreased, thus suggesting that enhanced H2AC methylation is coupled to Ser1p dephosphorylation. We show that H2A125Kme1 promotes interaction with the heterochromatin associated protein, HP1α. These specific changes in H2A are reversed by treatment with the AT(1R specific inhibitor losartan. Our analysis provides a first step towards an awareness of histone code regulation by GPCRs.

  17. A cleavable signal peptide enhances cell surface delivery and heterodimerization of Cerulean-tagged angiotensin II AT1 and bradykinin B2 receptor

    Energy Technology Data Exchange (ETDEWEB)

    Quitterer, Ursula, E-mail: [Molecular Pharmacology Unit, Swiss Federal Institute of Technology and University of Zurich, Zurich (Switzerland); Pohl, Armin; Langer, Andreas; Koller, Samuel; AbdAlla, Said [Molecular Pharmacology Unit, Swiss Federal Institute of Technology and University of Zurich, Zurich (Switzerland)


    Highlights: {yields} A new FRET-based method detects AT1/B2 receptor heterodimerization. {yields} First time application of AT1-Cerulean as a FRET donor. {yields} Method relies on signal peptide-enhanced cell surface delivery of AT1-Cerulean. {yields} A high FRET efficiency revealed efficient heterodimerization of AT1/B2R proteins. {yields} AT1/B2R heterodimers were functionally coupled to desensitization mechanisms. -- Abstract: Heterodimerization of the angiotensin II AT1 receptor with the receptor for the vasodepressor bradykinin, B2R, is known to sensitize the AT1-stimulated response of hypertensive individuals in vivo. To analyze features of that prototypic receptor heterodimer in vitro, we established a new method that uses fluorescence resonance energy transfer (FRET) and applies for the first time AT1-Cerulean as a FRET donor. The Cerulean variant of the green fluorescent protein as donor fluorophore was fused to the C-terminus of AT1, and the enhanced yellow fluorescent protein (EYFP) as acceptor fluorophore was fused to B2R. In contrast to AT1-EGFP, the AT1-Cerulean fusion protein was retained intracellularly. To facilitate cell surface delivery of AT1-Cerulean, a cleavable signal sequence was fused to the receptor's amino terminus. The plasma membrane-localized AT1-Cerulean resembled the native AT1 receptor regarding ligand binding and receptor activation. A high FRET efficiency of 24.7% between membrane-localized AT1-Cerulean and B2R-EYFP was observed with intact, non-stimulated cells. Confocal FRET microscopy further revealed that the AT1/B2 receptor heterodimer was functionally coupled to receptor desensitization mechanisms because activation of the AT1-Cerulean/B2R-EYFP heterodimer with a single agonist triggered the co-internalization of AT1/B2R. Receptor co-internalization was sensitive to inhibition of G protein-coupled receptor kinases, GRKs, as evidenced by a GRK-specific peptide inhibitor. In agreement with efficient AT1/B2R

  18. Combined blockade of AMPA and NMDA receptors in the brain of rats prevents pentylenetetrazole-induced clonic and tonic-clonic seizures without ataxia. (United States)

    Gmiro, V E; Serdyuk, S E


    Intramuscular injection of selective NMDA receptor antagonists memantine and arcaine 4-fold decreased the incidence of pentylenetetrazole-induced generalized tonic-clonic seizures in rats, while the incidence of clonic seizures decreased by 1.2-1.3 times. Memantine and arcaine are characterized by low therapeutic index, i.e. induced ataxia in rats in doses exceeding the effective anticonvulsant dose by only 3.5-10 times. Intramuscular injection of IEM-1913 (combined blockade of NMDA and AMPA receptors in the brain) decreased the incidence of pentylenetetrazole-induced clonic and tonic-clonic seizures in rats by 4-8 times. The therapeutic index of IEM-1913 surpassed that of memantine and arcaine by 200-600 times.

  19. Memory is preserved in older adults taking AT1 receptor blockers. (United States)

    Ho, Jean K; Nation, Daniel A


    Prior work suggests that some but not all antihypertensive treatments may benefit cognition and risk for Alzheimer's disease, independent of stroke. Angiotensin II receptor blockers (ARBs) have been highlighted as one antihypertensive drug class that may confer greatest benefit. The participants comprised 1626 nondemented adults, aged 55-91 years, recruited from Alzheimer's Disease Neuroimaging Initiative sites. Three groups were compared: ARB users (HTN-ARBs), other antihypertensive drug users (HTN-Other), and normotensives. In post hoc analyses, we also examined (1) users of ARBs and angiotensin-converting enzyme inhibitors (ACEIs), (2) users of blood-brain barrier (BBB)-crossing ARBs and users of non-BBB-crossing ARBs, and (3) users of BBB-crossing ARBs and ACEIs (BBB crossers) and users of non-BBB-crossing ARBs and ACEIs (BBB noncrossers). Groups were compared regarding cognition and magnetic resonance imaging measures of brain volume and white matter hyperintensities (WMH), using analysis of covariance and multilevel models. At baseline, the HTN-Other group performed worse than normotensives on Rey Auditory Verbal Learning Test (RAVLT) Immediate Recall (p = 0.002), Delayed Recall (p Memory (p = 0.001), and Trails A (p Memory (p = 0.04) and worse than normotensives on Trails A (p = 0.04). The HTN-Other group performed worse than normotensives on Logical Memory Immediate (p = 0.02) and Delayed Recall over the 3-year follow-up (p = 0.007). Over the follow-up period, those taking BBB-crossing ARBs performed better than the HTN-Other group on AVLT Delayed Recall (p = 0.04), Logical Memory Immediate (p = 0.02), and Delayed Recall (p = 0.05). They also had fewer WMH than the HTN-Other group (p = 0.008) and those taking non-BBB-crossing ARBs (p = 0.05). There were no group differences in brain volume. Users of BBB-crossing medications (ARBs or ACEIs) showed better performance on AVLT Delayed Recall over time than all

  20. Embryonic GABA(B receptor blockade alters cell migration, adult hypothalamic structure, and anxiety- and depression-like behaviors sex specifically in mice.

    Directory of Open Access Journals (Sweden)

    Matthew S Stratton

    Full Text Available Neurons of the paraventricular nucleus of the hypothalamus (PVN regulate the hypothalamic- pituitary-adrenal (HPA axis and the autonomic nervous system. Females lacking functional GABA(B receptors because of a genetic disruption of the R1 subunit have altered cellular characteristics in and around the PVN at birth. The genetic disruption precluded appropriate assessments of physiology or behavior in adulthood. The current study was conducted to test the long term impact of a temporally restricting pharmacological blockade of the GABA(B receptor to a 7-day critical period (E11-E17 during embryonic development. Experiments tested the role of GABA(B receptor signaling in fetal development of the PVN and later adult capacities for adult stress related behaviors and physiology. In organotypic slices containing fetal PVN, there was a female specific, 52% increase in cell movement speeds with GABA(B receptor antagonist treatment that was consistent with a sex-dependent lateral displacement of cells in vivo following 7 days of fetal exposure to GABA(B receptor antagonist. Anxiety-like and depression-like behaviors, open-field activity, and HPA mediated responses to restraint stress were measured in adult offspring of mothers treated with GABA(B receptor antagonist. Embryonic exposure to GABA(B receptor antagonist resulted in reduced HPA axis activation following restraint stress and reduced depression-like behaviors. There was also increased anxiety-like behavior selectively in females and hyperactivity in males. A sex dependent response to disruptions of GABA(B receptor signaling was identified for PVN formation and key aspects of physiology and behavior. These changes correspond to sex specific prevalence in similar human disorders, namely anxiety disorders and hyperactivity.

  1. Blood pressure reactivity to emotional stress is reduced in AT1A-receptor knockout mice on normal, but not high salt intake. (United States)

    Chen, Daian; La Greca, Luisa; Head, Geoffrey A; Walther, Thomas; Mayorov, Dmitry N


    Pharmacological evidence suggests that angiotensin II type 1 (AT(1)) receptors are involved in the regulation of cardiovascular response to emotional stress and reinforcing effect of dietary salt on this response. In this study, we examined the effect of genetic deletion of AT(1A) receptors on the cardiovascular effects of stress and salt in mice. AT(1A) receptor knockout (AT(1A)(-/-)) and wild-type (AT(1A)(+/+)) mice were implanted with telemetry devices and placed on a normal (0.4%) or high (3.1%) salt diet (HSD). Resting blood pressure (BP) in AT(1A)(-/-) mice (84+/-3 mm Hg) was lower than in AT(1A)(+/+) mice (107+/-2 mm Hg). Negative emotional (restraint) stress increased BP by 33+/-3 mm Hg in AT(1A)(+/+) mice. This response was attenuated by 40% in AT(1A)(-/-) mice (18+/-3 mm Hg). Conversely, the BP increase caused by food presentation and feeding was similar in AT(1A)(-/-) (25+/-3 mm Hg) and AT(1A)(+/+) mice (26+/-3 mm Hg). HSD increased resting BP by 14+/-4 mm Hg in AT(1A)(-/-) mice without affecting it significantly in AT(1A)(+/+) mice. Under these conditions, the pressor response to restraint stress in AT(1A)(-/-) mice (30+/-3 mm Hg) was no longer different from that in wild-type animals (28+/-3 mm Hg). The BP response to feeding was not altered by HSD in either AT(1A)(-/-) or AT(1A)(+/+) mice (25+/-2 and 27+/-3 mm Hg, respectively). These results indicate that AT(1A) receptor deficiency leads to a reduction in BP reactivity to negative emotional stress, but not feeding. HSD can selectively reinforce the cardiovascular response to negative stress in AT(1A)(-/-) mice. However, there is little interaction between AT(1A) receptors, excess dietary sodium and feeding-induced cardiovascular arousal.

  2. Angiotensin II-AT1receptor signaling is necessary for cyclooxygenase-2–dependent postnatal nephron generation

    DEFF Research Database (Denmark)

    Frölich, Stefanie; Slattery, Patrick; Thomas, Dominique


    Deletion of cyclooxygenase-2 (COX-2) causes impairment of postnatal kidney development. Here we tested whether the renin angiotensin system contributes to COX-2–dependent nephrogenesis in mice after birth and whether a rescue of impaired renal development and function in COX-2-/- mice was achieva......Deletion of cyclooxygenase-2 (COX-2) causes impairment of postnatal kidney development. Here we tested whether the renin angiotensin system contributes to COX-2–dependent nephrogenesis in mice after birth and whether a rescue of impaired renal development and function in COX-2-/- mice...... was achievable. Plasma renin concentration in mouse pups showed a birth peak and a second peak around day P8 during the first 10 days post birth. Administration of the angiotensin II receptor AT1 antagonist telmisartan from day P1 to P3 did not result in cortical damage. However, telmisartan treatment from day P...... development. Inhibition of the renin angiotensin system by aliskiren and enalapril caused similar glomerular defects as telmisartan. Administration of the AT1 receptor agonist L162313 to COX-2-/- pups improved kidney growth, ameliorated renal defects, but had no beneficial effect on reduced cortical mass. L...

  3. GABA(A) receptor blockade in dorsomedial and ventromedial nuclei of the hypothalamus evokes panic-like elaborated defensive behaviour followed by innate fear-induced antinociception. (United States)

    Freitas, Renato Leonardo; Uribe-Mariño, Andrés; Castiblanco-Urbina, Maria Angélica; Elias-Filho, Daoud Hibraim; Coimbra, Norberto Cysne


    Dysfunction in the hypothalamic GABAergic system has been implicated in panic syndrome in humans. Furthermore, several studies have implicated the hypothalamus in the elaboration of pain modulation. Panic-prone states are able to be experimentally induced in laboratory animals to study this phenomenon. The aim of the present work was to investigate the involvement of medial hypothalamic nuclei in the organization of panic-like behaviour and the innate fear-induced oscillations of nociceptive thresholds. The blockade of GABA(A) receptors in the neuronal substrates of the ventromedial or dorsomedial hypothalamus was followed by elaborated defensive panic-like reactions. Moreover, innate fear-induced antinociception was consistently elicited after the escape behaviour. The escape responses organized by the dorsomedial and ventromedial hypothalamic nuclei were characteristically more elaborated, and a remarkable exploratory behaviour was recorded during GABA(A) receptor blockade in the medial hypothalamus. The motor characteristic of the elaborated defensive escape behaviour and the patterns of defensive alertness and defensive immobility induced by microinjection of the bicuculline either into the dorsomedial or into the ventromedial hypothalamus were very similar. This was followed by the same pattern of innate fear-induced antinociceptive response that lasted approximately 40 min after the elaborated defensive escape reaction in both cases. These findings suggest that dysfunction of the GABA-mediated neuronal system in the medial hypothalamus causes panic-like responses in laboratory animals, and that the elaborated escape behaviour organized in both dorsomedial and ventromedial hypothalamic nuclei are followed by significant innate-fear-induced antinociception. Our findings indicate that the GABA(A) receptor of dorsomedial and ventromedial hypothalamic nuclei are critically involved in the modulation of panic-like behaviour.

  4. Blockade of adenosine A2A receptors prevents interleukin-1β-induced exacerbation of neuronal toxicity through a p38 mitogen-activated protein kinase pathway

    Directory of Open Access Journals (Sweden)

    Simões Ana


    Full Text Available Abstract Background and purpose Blockade of adenosine A2A receptors (A2AR affords robust neuroprotection in a number of brain conditions, although the mechanisms are still unknown. A likely candidate mechanism for this neuroprotection is the control of neuroinflammation, which contributes to the amplification of neurodegeneration, mainly through the abnormal release of pro-inflammatory cytokines such as interleukin(IL-1β. We investigated whether A2AR controls the signaling of IL-1β and its deleterious effects in cultured hippocampal neurons. Methods Hippocampal neuronal cultures were treated with IL-1β and/or glutamate in the presence or absence of the selective A2AR antagonist, SCH58261 (50 nmol/l. The effect of SCH58261 on the IL-1β-induced phosphorylation of the mitogen-activated protein kinases (MAPKs c-Jun N-terminal kinase (JNK and p38 was evaluated by western blotting and immunocytochemistry. The effect of SCH58261 on glutamate-induced neurodegeneration in the presence or absence of IL-1β was evaluated by nucleic acid and by propidium iodide staining, and by lactate dehydrogenase assay. Finally, the effect of A2AR blockade on glutamate-induced intracellular calcium, in the presence or absence of IL-1β, was studied using single-cell calcium imaging. Results IL-1β (10 to 100 ng/ml enhanced both JNK and p38 phosphorylation, and these effects were prevented by the IL-1 type 1 receptor antagonist IL-1Ra (5 μg/ml, in accordance with the neuronal localization of IL-1 type 1 receptors, including pre-synaptically and post-synaptically. At 100 ng/ml, IL-1β failed to affect neuronal viability but exacerbated the neurotoxicity induced by treatment with 100 μmol/l glutamate for 25 minutes (evaluated after 24 hours. It is likely that this resulted from the ability of IL-1β to enhance glutamate-induced calcium entry and late calcium deregulation, both of which were unaffected by IL-1β alone. The selective A2AR antagonist, SCH58261 (50 nmol

  5. Cross talk between AT1 receptors and Toll-like receptor 4 in microglia contributes to angiotensin II-derived ROS production in the hypothalamic paraventricular nucleus. (United States)

    Biancardi, Vinicia Campana; Stranahan, Alexis M; Krause, Eric G; de Kloet, Annette D; Stern, Javier E


    ANG II is thought to increase sympathetic outflow by increasing oxidative stress and promoting local inflammation in the paraventricular nucleus (PVN) of the hypothalamus. However, the relative contributions of inflammation and oxidative stress to sympathetic drive remain poorly understood, and the underlying cellular and molecular targets have yet to be examined. ANG II has been shown to enhance Toll-like receptor (TLR)4-mediated signaling on microglia. Thus, in the present study, we aimed to determine whether ANG II-mediated activation of microglial TLR4 signaling is a key molecular target initiating local oxidative stress in the PVN. We found TLR4 and ANG II type 1 (AT1) receptor mRNA expression in hypothalamic microglia, providing molecular evidence for the potential interaction between these two receptors. In hypothalamic slices, ANG II induced microglial activation within the PVN (∼65% increase, P < 0.001), an effect that was blunted in the absence of functional TLR4. ANG II increased ROS production, as indicated by dihydroethidium fluorescence, within the PVN of rats and mice (P < 0.0001 in both cases), effects that were also dependent on the presence of functional TLR4. The microglial inhibitor minocycline attenuated ANG II-mediated ROS production, yet ANG II effects persisted in PVN single-minded 1-AT1a knockout mice, supporting the contribution of a non-neuronal source (likely microglia) to ANG II-driven ROS production in the PVN. Taken together, these results support functional interactions between AT1 receptors and TLR4 in mediating ANG II-dependent microglial activation and oxidative stress within the PVN. More broadly, our results support a functional interaction between the central renin-angiotensin system and innate immunity in the regulation of neurohumoral outflows from the PVN. Copyright © 2016 the American Physiological Society.

  6. Targeting myeloid-derived suppressor cells with colony stimulating factor-1 receptor blockade can reverse immune resistance to immunotherapy in indoleamine 2,3-dioxygenase-expressing tumors. (United States)

    Holmgaard, Rikke B; Zamarin, Dmitriy; Lesokhin, Alexander; Merghoub, Taha; Wolchok, Jedd D


    Tumor indoleamine 2,3-dioxygenase (IDO) promotes immunosuppression by direct action on effector T cells and Tregs and through recruitment, expansion and activation of myeloid-derived suppressor cells (MDSCs). Targeting of MDSCs is clinically being explored as a therapeutic strategy, though optimal targeting strategies and biomarkers predictive of response are presently unknown. Maturation and tumor recruitment of MDSCs are dependent on signaling through the receptor tyrosine kinase CSF-1R on myeloid cells. Here, we show that MDSCs are the critical cell population in IDO-expressing B16 tumors in mediating accelerated tumor outgrowth and resistance to immunotherapy. Using a clinically relevant drug, we show that inhibition of CSF-1R signaling can functionally block tumor-infiltrating MDSCs and enhance anti-tumor T cell responses. Furthermore, inhibition of CSF-1R sensitizes IDO-expressing tumors to immunotherapy with T cell checkpoint blockade, and combination of CSF-1R blockade with IDO inhibitors potently elicits tumor regression. These findings provide evidence for a critical and functional role for MDSCs on the in vivo outcome of IDO-expressing tumors. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  7. Blockade of cannabinoid CB receptor function protects against in vivo disseminating brain damage following NMDA-induced excitotoxicity

    DEFF Research Database (Denmark)

    Hansen, H.H.; Ramos, J.A.; Fernández-Ruiz, J.


    The ability of cannabinoid CB, receptors to influence glutamatergic excitatory neurotransmission has fueled interest in how these receptors and their endogenous ligands may interact in conditions of excitotoxic insults. The present study characterized the impact of stimulated and inhibited CB...

  8. A randomized trial on mineralocorticoid receptor blockade in men: effects on stress responses, selective attention, and memory

    NARCIS (Netherlands)

    Cornelisse, S.; Joëls, M.; Smeets, T.


    Corticosteroids, released in high amounts after stress, exert their effects via two different receptors in the brain: glucocorticoid receptors (GRs) and mineralocorticoid receptors (MRs). GRs have a role in normalizing stress-induced effects and promoting consolidation, while MRs are thought to be

  9. Renin angiotensin system blockade reduces urinary levels of soluble urokinase plasminogen activator receptor (suPAR) in patients with type 2 diabetes

    DEFF Research Database (Denmark)

    Persson, Frederik; Theilade, Simone; Eugen-Olsen, Jesper


    Soluble urokinase plasminogen activator receptor (suPAR) is associated with faster decline in kidney function and the pathogenesis of diabetic nephropathy. However, little is known about the impact of treatment on plasma and urinary levels of suPAR. We aimed to investigate the impact of renin...... angiotensin system (RAS) single and dual blockade on suPAR levels in patients with type 2 diabetes and albuminuria. We conducted a post-hoc analysis of a randomized controlled crossover trial. Urine and plasma samples were analyzed for suPAR levels. The placebo period was considered reference and all.......1) and urine levels were 4.0 ng/mL (1.1). None of the treatments had significant effects on plasma levels of suPAR compared to placebo. Compared to placebo, irbesartan and combination treatment decreased urinary levels of suPAR significantly (-1.3 ng/mL), while aliskiren did not. In patients with type 2...

  10. Dopaminergic modulation of hippocampus-dependent learning: blockade of hippocampal D1-class receptors during learning impairs 1-trial place memory at a 30-min retention delay. (United States)

    Pezze, Marie; Bast, Tobias


    Consistent with the requirement of D1-class dopamine receptors for the induction of late (>3 h) hippocampal long-term potentiation (LTP), hippocampus-dependent 1-trial memory at long retention delays (>6 h) requires hippocampal D1-class receptors during learning. Hippocampal D1-class receptors also modulate the induction and magnitude of early LTP (hippocampus-dependent early (memory remains to be revealed. We addressed this conceptually important issue, using a novel modification of the watermaze delayed-matching-to-place (DMP) test with an improved measure of hippocampus-dependent 1-trial place memory. On the DMP test, rats learn the novel location of a hidden escape platform on trial 1 of every day, so that 1-trial place memory can be measured on trial 2. Our new task modification includes the measurement of search preference for the correct location on trial 2 - a very sensitive index of hippocampus-dependent place memory. We examined the effects of hippocampal D1-class receptor blockade or stimulation during learning on memory at a 30-min retention delay. Bilateral hippocampal infusion of the D1-class receptor antagonist SCH23390 (1 or 5 μg/1 μl/side) before trial 1 dose-dependently impaired such early memory: rats infused with the higher dose showed reduced search preference for the correct location and took longer paths to reach this location. Infusion of the D1-class partial agonist SKF38393 (1 or 5 μg/1 μl/side) did not affect measures of 1-trial place memory. Our data reveal a behavioural correlate of the dopaminergic modulation of early LTP, thereby supporting the close correspondence between hippocampal LTP and hippocampus-dependent learning. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Pharmacological or genetic blockade of the dopamine D3 receptor increases cell proliferation in the hippocampus of adult mice. (United States)

    Egeland, Martin; Zhang, Xiaoqun; Millan, Mark J; Mocaer, Elisabeth; Svenningsson, Per


    Dopamine plays an important role in cellular processes controlling the functional and structural plasticity of neurons, as well as their generation and proliferation, both in the developing and the adult brain. The precise roles of individual dopamine receptors subtypes in adult neurogenesis remain poorly defined, although D3 receptors are known to be involved in neurogenesis in the subventricular zone. By contrast, very few studies have addressed the influence of dopamine and D3 receptors upon neurogenesis in the subgranular zone of the hippocampus, an issue addressed herein employing constitutive D3 receptor knockout mice, or chronic exposure to the preferential D3 receptor antagonist, S33138. D3 receptor knockout mice revealed increased baseline levels of cell proliferation and ongoing neurogenesis, as measured both using Ki-67 and doublecortin, whereas there was no difference in cell survival as measured by BrdU (5-bromo-2'-deoxyuridine). Chronic administration of S33138 was shown to be functionally active in enhancing levels of the plasticity-related molecule, delta-FosB, in the D3 receptor-rich nucleus accumbens. In accordance with the stimulated neurogenesis seen in D3 receptor knockout mice, S33138 increased proliferation in wild-type mice. These observations suggest that D3 receptors exert a tonic, constitutive inhibitory influence upon adult hippocampal neurogenesis. © 2012 The Authors Journal of Neurochemistry © 2012 International Society for Neurochemistry.

  12. Irreversible renal damage after transient renin-angiotensin system stimulation: involvement of an AT1-receptor mediated immune response.

    Directory of Open Access Journals (Sweden)

    Bart F J Heijnen

    Full Text Available Transient activation of the renin-angiotensin system (RAS induces irreversible renal damage causing sustained elevation in blood pressure (BP in Cyp1a1-Ren2 transgenic rats. In our current study we hypothesized that activation of the AT1-receptor (AT1R leads to a T-cell response causing irreversible impairment of renal function and hypertension. Cyp1a1-Ren2 rats harbor a construct for activation of the RAS by indole-3-carbinol (I3C. Rats were fed a I3C diet between 4-8 weeks of age to induce hypertension. Next, I3C was withdrawn and rats were followed-up for another 12 weeks. Additional groups received losartan (20 mg/kg/day or hydralazine (100 mg/kg/day treatment between 4-8 weeks. Rats were placed for 24h in metabolic cages before determining BP at week 8, 12 and 20. At these ages, subsets of animals were sacrificed and the presence of kidney T-cell subpopulations was investigated by immunohistochemistry and molecular marker analysis. The development of sustained hypertension was completely prevented by losartan, whereas hydralazine only caused a partial decrease in BP. Markers of renal damage: KIM-1 and osteopontin were highly expressed in urine and kidney samples of I3C-treated rats, even until 20 weeks of age. Additionally, renal expression of regulatory-T cells (Tregs was highly increased in I3C-treated rats, whereas the expression of T-helper 1 (Th1 cells demonstrated a strong decrease. Losartan prevented these effects completely, whereas hydralazine was unable to affect these changes. In young Cyp1a1-Ren2 rats AT1R activation leads to induction of an immune response, causing a shift from Th1-cells to Tregs, contributing to the development of irreversible renal damage and hypertension.

  13. Adenosine A2A receptor blockade prevents synaptotoxicity and memory dysfunction caused by beta-amyloid peptides via p38 mitogen-activated protein kinase pathway. (United States)

    Canas, Paula M; Porciúncula, Lisiane O; Cunha, Geanne M A; Silva, Carla G; Machado, Nuno J; Oliveira, Jorge M A; Oliveira, Catarina R; Cunha, Rodrigo A


    Alzheimer's disease (AD) is characterized by memory impairment, neurochemically by accumulation of beta-amyloid peptide (namely Abeta(1-42)) and morphologically by an initial loss of nerve terminals. Caffeine consumption prevents memory dysfunction in different models, which is mimicked by antagonists of adenosine A(2A) receptors (A(2A)Rs), which are located in synapses. Thus, we now tested whether A(2A)R blockade prevents the early Abeta(1-42)-induced synaptotoxicity and memory dysfunction and what are the underlying signaling pathways. The intracerebral administration of soluble Abeta(1-42) (2 nmol) in rats or mice caused, 2 weeks later, memory impairment (decreased performance in the Y-maze and object recognition tests) and a loss of nerve terminal markers (synaptophysin, SNAP-25) without overt neuronal loss, astrogliosis, or microgliosis. These were prevented by pharmacological blockade [5-amino-7-(2-phenylethyl)-2-(2-furyl)-pyrazolo[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidine (SCH58261); 0.05 mg . kg(-1) . d(-1), i.p.; for 15 d] in rats, and genetic inactivation of A(2A)Rs in mice. Moreover, these were synaptic events since purified nerve terminals acutely exposed to Abeta(1-42) (500 nm) displayed mitochondrial dysfunction, which was prevented by A(2A)R blockade. SCH58261 (50 nm) also prevented the initial synaptotoxicity (loss of MAP-2, synaptophysin, and SNAP-25 immunoreactivity) and subsequent loss of viability of cultured hippocampal neurons exposed to Abeta(1-42) (500 nm). This A(2A)R-mediated control of neurotoxicity involved the control of Abeta(1-42)-induced p38 phosphorylation and was independent from cAMP/PKA (protein kinase A) pathway. Together, these results show that A(2A)Rs play a crucial role in the development of Abeta-induced synaptotoxicity leading to memory dysfunction through a p38 MAPK (mitogen-activated protein kinase)-dependent pathway and provide a molecular basis for the benefits of caffeine consumption in AD.

  14. Intact discrimination reversal learning but slowed responding to reward-predictive cues after dopamine D1 and D2 receptor blockade in the nucleus accumbens of rats. (United States)

    Calaminus, Carsten; Hauber, Wolfgang


    The prediction error hypothesis of dopamine action states that dopamine signals are necessary for the brain to update the predictive significance of cues. Yet, little is known whether D1 or D2 receptor-mediated signals in the nucleus accumbens core (AcbC) are required to learn a reversal of the predictive significance of cues. Here we examined the effects of a selective D1 or D2 receptor blockade in the AcbC on learning a reversal of previously acquired cue-reward magnitude contingencies. Rats were trained on a reaction time (RT) task demanding conditioned lever release with discriminative visual cues signalling in advance the upcoming reward magnitude (one or five food pellets). After acquisition, RTs were guided by cue-associated reward magnitudes, i.e. RTs of responses were significantly shorter for expected high vs low reward. Thereafter, cue-reward magnitude contingencies were reversed. Reversal learning was tested for 12 daily sessions with intra-AcbC micro-infusions being given on sessions 1-6. Subjects received pre-trial infusions of the selective D1 or D2 receptor antagonists, SCH23390 (0.5, 2 microg per side) or raclopride (1, 4 microg per side), or vehicle (0.5 microl). Intra-AcbC infusion of SCH23390 (0.5, 2 microg) or raclopride (1, 4 microg) did not inhibit discrimination reversal learning, but the higher dose of each drug increased RTs of instrumental responses. In a visual discrimination task as used here, D1 and D2 receptor-mediated signals in the AcbC seem to be unnecessary in updating the reward-predictive significance of cues, rather, they serve to activate instrumental behaviour.

  15. P2Y12 Receptor Localizes in the Renal Collecting Duct and Its Blockade Augments Arginine Vasopressin Action and Alleviates Nephrogenic Diabetes Insipidus. (United States)

    Zhang, Yue; Peti-Peterdi, Janos; Müller, Christa E; Carlson, Noel G; Baqi, Younis; Strasburg, David L; Heiney, Kristina M; Villanueva, Karie; Kohan, Donald E; Kishore, Bellamkonda K


    P2Y12 receptor (P2Y12-R) signaling is mediated through Gi, ultimately reducing cellular cAMP levels. Because cAMP is a central modulator of arginine vasopressin (AVP)-induced water transport in the renal collecting duct (CD), we hypothesized that if expressed in the CD, P2Y12-R may play a role in renal handling of water in health and in nephrogenic diabetes insipidus. We found P2Y12-R mRNA expression in rat kidney, and immunolocalized its protein and aquaporin-2 (AQP2) in CD principal cells. Administration of clopidogrel bisulfate, an irreversible inhibitor of P2Y12-R, significantly increased urine concentration and AQP2 protein in the kidneys of Sprague-Dawley rats. Notably, clopidogrel did not alter urine concentration in Brattleboro rats that lack AVP. Clopidogrel administration also significantly ameliorated lithium-induced polyuria, improved urine concentrating ability and AQP2 protein abundance, and reversed the lithium-induced increase in free-water excretion, without decreasing blood or kidney tissue lithium levels. Clopidogrel administration also augmented the lithium-induced increase in urinary AVP excretion and suppressed the lithium-induced increase in urinary nitrates/nitrites (nitric oxide production) and 8-isoprostane (oxidative stress). Furthermore, selective blockade of P2Y12-R by the reversible antagonist PSB-0739 in primary cultures of rat inner medullary CD cells potentiated the expression of AQP2 and AQP3 mRNA, and cAMP production induced by dDAVP (desmopressin). In conclusion, pharmacologic blockade of renal P2Y12-R increases urinary concentrating ability by augmenting the effect of AVP on the kidney and ameliorates lithium-induced NDI by potentiating the action of AVP on the CD. This strategy may offer a novel and effective therapy for lithium-induced NDI. Copyright © 2015 by the American Society of Nephrology.

  16. [Blockade of the alpha3alpha4 N-cholinoreceptors and GluR1 AMPA receptors eliminates clonic-tonic nicotinic and kainate seizures]. (United States)

    Serdiuk, S E; Gmiro, V E


    Monoammonium N-alkyl derivative of decylamine (IEM-1678), which blocks alpha3beta4 N-cholinoreceptors (but does not block GluR1 AMPA receptors), in doses of 1.0 - 3.0 mg/kg produces a 4-fold decrease in the frequency and lethality of nicotinic clonic-tonic seizures. However, even in the maximum dose of 3 mg/kg, IEM-1678 only slightly decreases kainate clonic-tonic seizures. Bis-ammonium compound IEM-1460 (containing adamantyl radical), which blocks both GluR1 AMPA receptors and alpha3beta4 N-cholinoreceptors, in a range of doses 0.1 - 3 mg/kg produces a 5- to 8-fold decrease in the frequency and virtually completely eliminates lethality of both clonic-tonic nicotinic and kainate seizures. Hence, the complete elimination of generalized kainate and nicotinic seizures requires combined blockade GluR1 AMPA and alpha3beta4 N-cholinoreceptors.

  17. Kinetic characterization of the phencyclidine-N-methyl-D-aspartate receptor interaction: evidence for a steric blockade of the channel

    Energy Technology Data Exchange (ETDEWEB)

    Kloog, Y.; Haring, R.; Sokolovsky, M.


    The nature of the interactions between the N-methyl-D-aspartate (NMDA) and the phencyclidine (PCP) receptors was studied in membranes obtained from rat cerebral cortex and washed repeatedly to remove endogenous excitatory amino acids. Binding of (/sup 3/H)-N-(1-(2-thienyl)cyclohexyl)piperidine ((/sup 3/H)TCP) to its receptor sites in these membranes proceeded slowly and did not reach equilibrium even after incubation for 4 h at 25/sup 0/C. The dissociation rate of (/sup 3/H)TCP-receptor complexes was also slow. Both association and dissociation followed first-order reaction kinetics. Addition of glutamate and glycine to the washed membranes was immediately followed by a marked increase in the rates of both association of (/sup 3/H)TCP with the receptors and its dissociation from them. Association now followed second-order reaction kinetics. Accelerated association of (/sup 3/H)TCP with its binding sites could also be induced by NMDA or by glutamate alone, and glycine enhanced the effect. The binding data were fitted to a model in which interactions of (/sup 3/H)TCP with the receptor involve a two-step process: the outside ligand must cross a barrier (presumably a closed NMDA receptor channel in the absence of agonists). Once agonists are added, this limitation is removed. The excellent agreement between the kinetic and equilibrium binding parameters with the predictions of the model, as well as with previous electrophysiological data on the mode of noncompetitive blocking of the NMDA receptor channel by PCP-like drugs, suggests that these drugs are steric blockers of the channel and prefer its open state.

  18. Activation and blockade of serotonin7 receptors in the prelimbic cortex regulate depressive-like behaviors in a 6-hydroxydopamine-induced Parkinson's disease rat model. (United States)

    Zhang, Q J; Du, C X; Tan, H H; Zhang, L; Li, L B; Zhang, J; Niu, X L; Liu, J


    The role of serotonin7 (5-HT7) receptors in the regulation of depression is poorly understood, particularly in Parkinson's disease-associated depression. Here we examined whether 5-HT7 receptors in the prelimbic (PrL) sub-region of the ventral medial prefrontal cortex (mPFC) involve in the regulation of depressive-like behaviors in sham-operated rats and rats with unilateral 6-hydroxydopamine lesions of the medial forebrain bundle. The lesion induced depressive-like responses as measured by the sucrose preference and forced swim tests when compared to sham-operated rats. Intra-PrL injection of 5-HT7 receptor agonist AS19 (0.5, 1 and 2 μg/rat) increased sucrose consumption, and decreased immobility time in sham-operated and the lesioned rats, indicating the induction of antidepressant-like effects. Further, intra-PrL injection of 5-HT7 receptor antagonist SB269970 (1.5, 3 and 6 μg/rat) decreased sucrose consumption, and increased immobility time, indicating the induction of depressive-like responses. However, the doses producing these effects in the lesioned rats were higher than those in sham-operated rats. Neurochemical results showed that intra-PrL injection of AS19 (2 μg/rat) increased dopamine, 5-hydroxytryptamine (5-HT) and noradrenaline (NA) levels in the mPFC, habenula and ventral hippocampus (vHip) in sham-operated and the lesioned rats; whereas SB269970 (6 μg/rat) decreased 5-HT levels in the habenula and vHip, and the levels of NA in the mPFC, habenula and vHip in the two groups of rats. The results suggest that 5-HT7 receptors in the PrL play an important role in the regulation of these behaviors, which attribute to changes in monoamine levels in the limbic and limbic-related brain regions after activation and blockade of 5-HT7 receptors. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

  19. Angiotensin II type 1 receptor blockade partially attenuates hypoxia-induced pulmonary hypertension in newborn piglets: relationship with the nitrergic system

    Energy Technology Data Exchange (ETDEWEB)

    Camelo, J.S. Jr. [Departamento de Puericultura e Pediatria, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Martins, A.R. [Departamento de Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Instituto de Ciências Biológicas, Universidade Federal do Triângulo Mineiro, Uberaba, MG (Brazil); Rosa, E. [Departamento de Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Ramos, S.G. [Departamento de Patologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SPBrasil (Brazil); Hehre, D.; Bancalari, E.; Suguihara, C. [Department of Pediatrics, Division of Neonatology, Neonatal Developmental Biology Laboratory, University of Miami Miller School of Medicine, Miami, FL (United States)


    The objective of this study was to observe possible interactions between the renin-angiotensin and nitrergic systems in chronic hypoxia-induced pulmonary hypertension in newborn piglets. Thirteen chronically instrumented newborn piglets (6.3 ± 0.9 days; 2369 ± 491 g) were randomly assigned to receive saline (placebo, P) or the AT{sub 1} receptor (AT{sub 1}-R) blocker L-158,809 (L) during 6 days of hypoxia (FiO{sub 2} = 0.12). During hypoxia, pulmonary arterial pressure (Ppa; P < 0.0001), pulmonary vascular resistance (PVR; P < 0.02) and the pulmonary to systemic vascular resistance ratio (PVR/SVR; P < 0.05) were significantly attenuated in the L (N = 7) group compared to the P group (N = 6). Western blot analysis of lung proteins showed a significant decrease of endothelial NOS (eNOS) in both P and L animals, and of AT{sub 1}-R in P animals during hypoxia compared to normoxic animals (C group, N = 5; P < 0.01 for all groups). AT{sub 1}-R tended to decrease in L animals. Inducible NOS (iNOS) did not differ among P, L, and C animals and iNOS immunohistochemical staining in macrophages was significantly more intense in L than in P animals (P < 0.01). The vascular endothelium showed moderate or strong eNOS and AT{sub 1}-R staining. Macrophages and pneumocytes showed moderate or strong iNOS and AT{sub 1}-R staining, but C animals showed weak iNOS and AT{sub 1}-R staining. Macrophages of L and P animals showed moderate and weak AT{sub 2}-R staining, respectively, but the endothelium of all groups only showed weak staining. In conclusion, pulmonary hypertension induced by chronic hypoxia in newborn piglets is partially attenuated by AT{sub 1}-R blockade. We suggest that AT{sub 1}-R blockade might act through AT{sub 2}-R and/or Mas receptors and the nitrergic system in the lungs of hypoxemic newborn piglets.

  20. Blockade of the growth hormone (GH) receptor unmasks rapid GH-releasing peptide-6-mediated tissue-specific insulin resistance

    NARCIS (Netherlands)

    A.F. Muller (Alex); L.J. Hofland (Leo); S.W.J. Lamberts (Steven); M. Bidlingmaier (Martin); C.J. Strasburger; J.A.M.J.L. Janssen (Joseph); A-J. van der Lely (Aart-Jan)


    textabstractThe roles of GH and its receptor (GHR) in metabolic control are not yet fully understood. We studied the roles of GH and the GHR using the GHR antagonist pegvisomant for metabolic control of healthy nonobese men in fasting and nonfasting conditions. Ten

  1. Individualized prediction of the effect of angiotensin receptor blockade on renal and cardiovascular outcomes in patients with diabetic nephropathy.

    NARCIS (Netherlands)

    van der Sande, NGC; Dorresteijn, JAN; Visseren, FLJ; Dwyer, J.P.; Blankestijn, p; van der Graaf, Y; Heerspink, H. J Lambers


    Aims: To predict individualized treatment effects of angiotensin receptor blockers (ARBs) on cardiovascular and renal complications in order to help clinicians and patients assess the benefit of treatment (or adherence) and estimate remaining disease risk. Materials and methods: In patients with

  2. Pharmacological blockade of serotonin 5-HT₇ receptor reverses working memory deficits in rats by normalizing cortical glutamate neurotransmission.

    Directory of Open Access Journals (Sweden)

    Pascal Bonaventure

    Full Text Available The role of 5-HT₇ receptor has been demonstrated in various animal models of mood disorders; however its function in cognition remains largely speculative. This study evaluates the effects of SB-269970, a selective 5-HT₇ antagonist, in a translational model of working memory deficit and investigates whether it modulates cortical glutamate and/or dopamine neurotransmission in rats. The effect of SB-269970 was evaluated in the delayed non-matching to position task alone or in combination with MK-801, a non-competitive NMDA receptor antagonist, and, in separate experiments, with scopolamine, a non-selective muscarinic antagonist. SB-269970 (10 mg/kg significantly reversed the deficits induced by MK-801 (0.1 mg/kg but augmented the deficit induced by scopolamine (0.06 mg/kg. The ability of SB-269970 to modulate MK-801-induced glutamate and dopamine extracellular levels was separately evaluated using biosensor technology and microdialysis in the prefrontal cortex of freely moving rats. SB-269970 normalized MK-801 -induced glutamate but not dopamine extracellular levels in the prefrontal cortex. Rat plasma and brain concentrations of MK-801 were not affected by co-administration of SB-269970, arguing for a pharmacodynamic rather than a pharmacokinetic mechanism. These results indicate that 5-HT₇ receptor antagonists might reverse cognitive deficits associated with NMDA receptor hypofunction by selectively normalizing glutamatergic neurotransmission.

  3. Glucocorticoid effects on the programming of AT1b angiotensin receptor gene methylation and expression in the rat.

    Directory of Open Access Journals (Sweden)

    Irina Bogdarina


    Full Text Available Adverse events in pregnancy may 'programme' offspring for the later development of cardiovascular disease and hypertension. Previously, using a rodent model of programmed hypertension we have demonstrated the role of the renin-angiotensin system in this process. More recently we showed that a maternal low protein diet resulted in undermethylation of the At1b angiotensin receptor promoter and the early overexpression of this gene in the adrenal of offspring. Here, we investigate the hypothesis that maternal glucocorticoid modulates this effect on fetal DNA methylation and gene expression. We investigated whether treatment of rat dams with the 11beta-hydroxylase inhibitor metyrapone, could prevent the epigenetic and gene expression changes we observed. Offspring of mothers subjected to a low protein diet in pregnancy showed reduced adrenal Agtr1b methylation and increased adrenal gene expression as we observed previously. Treatment of mothers with metyrapone for the first 14 days of pregnancy reversed these changes and prevented the appearance of hypertension in the offspring at 4 weeks of age. As a control for non-specific effects of programmed hypertension we studied offspring of mothers treated with dexamethasone from day 15 of pregnancy and showed that, whilst they had raised blood pressure, they failed to show any evidence of Agtr1b methylation or increase in gene expression. We conclude that maternal glucocorticoid in early pregnancy may induce changes in methylation and expression of the Agtr1b gene as these are clearly reversed by an 11 beta-hydroxylase inhibitor. However in later pregnancy a converse effect with dexamethasone could not be demonstrated and this may reflect either an alternative mechanism of this glucocorticoid or a stage-specific influence.

  4. Recovery from ketamine-induced amnesia by blockade of GABA-A receptor in the medial prefrontal cortex of mice. (United States)

    Farahmandfar, Maryam; Akbarabadi, Ardeshir; Bakhtazad, Atefeh; Zarrindast, Mohammad-Reza


    Ketamine and other noncompetitive N-methyl-d-aspartate (NMDA) receptor antagonists are known to induce deficits in learning and cognitive performance sensitive to prefrontal cortex (PFC) functions. The interaction of a glutamatergic and GABAergic systems is essential for many cognitive behaviors. In order to understand the effect of γ-aminobutyric acid (GABA)/glutamate interactions on learning and memory, we investigated the effects of intra medial prefrontal cortex (mPFC) injections of GABAergic agents on ketamine-induced amnesia using a one-trial passive avoidance task in mice. Pre-training systemic administration of ketamine (5, 10 and 15mg/kg, i.p.) dose-dependently decreased the memory acquisition of a one-trial passive avoidance task. Pre-training intra-mPFC injection of muscimol, GABAA receptor agonist (0.05, 0.1 and 0.2μg/mouse) and baclofen GABAB receptor agonist (0.05, 0.1, 0.5 and 1μg/mouse), impaired memory acquisition. However, co-pretreatment of different doses of muscimol and baclofen with a lower dose of ketamine (5mg/kg), which did not induce amnesia by itself, caused inhibition of memory formation. Our data showed that sole pre-training administration of bicuculline, GABA-A receptor antagonist and phaclofen GABA-B receptor antagonist into the mPFC, did not affect memory acquisition. In addition, the amnesia induced by pre-training ketamine (15mg/kg) was significantly decreased by the pretreatment of bicuculline (0.005, 0.1 and 0.5μg/mouse). It can be concluded that GABAergic system of the mPFC is involved in the ketamine-induced impairment of memory acquisition. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

  5. Cerebrovascular ETB, 5-HT1B, and AT1 receptor upregulation correlates with reduction in regional CBF after subarachnoid hemorrhage

    DEFF Research Database (Denmark)

    Ansar, Saema; Vikman, Petter; Nielsen, Marianne


    We hypothesize that cerebral ischemia leads to enhanced expression of endothelin (ET), 5-hydroxytryptamine (5-HT), and angiotensin II (ANG II) receptors in the vascular smooth muscle cells. Our aim is to correlate the upregulation of cerebrovascular receptors and the underlying molecular mechanisms...... levels. These changes occur in parallel with a successive decrease in CBF. Thus there is a temporal correlation between the changes in receptor expression and CBF reduction, suggesting a linkage....

  6. Extracellular quaternary ammonium blockade of transient receptor potential vanilloid subtype 1 channels expressed in Xenopus laevis oocytes

    DEFF Research Database (Denmark)

    Rivera-Acevedo, Ricardo E; Pless, Stephan Alexander; Schwarz, Stephan K W


    Transient receptor potential vanilloid subtype 1 (TRPV1) channels are essential nociceptive integrators in primary afferent neurons. These nonselective cation channels are inhibited by local anesthetic compounds through an undefined mechanism. Here, we show that lidocaine inhibits TRPV1 channels...... expressed in Xenopus laevis oocytes, whereas the neutral local anesthetic, benzocaine, does not, suggesting that a titratable amine is required for high-affinity inhibition. Consistent with this possibility, extracellular tetraethylammonium (TEA) and tetramethylammonium application produces potent, voltage...

  7. The antifibrotic effects of alveolar macrophages 5-HT2C receptors blockade on bleomycin-induced pulmonary fibrosis in rats. (United States)

    Elaidy, Samah M; Essawy, Soha S


    The most widespread chronic fibrosing lung disease is idiopathic pulmonary fibrosis. Lung serotonin (5-HT) content is increased during pulmonary fibrosis with the implication of 5-HT2 receptors in the pathogenesis. Serotonin plays important roles in alveolar macrophages function through 5-HT2C receptors activation. Numerous studies described the important role of 5-HT2A/B receptor blockers in suppressing different types of fibrosis as idiopathic pulmonary fibrosis. The current study pointed to examine the antifibrotic effects of RS-102221 and/or terguride through in vivo model of pulmonary fibrosis. Induction of pulmonary fibrosis was through a single dose of intra-tracheal bleomycin instillation (5mg/kg dissolved in phosphate buffer saline) in adult male albino Wistar rats. Next day of bleomycin instillation, intraperitoneal injection of RS-102221 (0.5mg/kg/d) and/or terguride (1.2mg/kg/d) were administered and continued for 14 days. Noticeable increase in 5-HT2C receptors expression was observed in fibrotic lung tissues with marked allocation belonging to alveolar macrophages. Either RS-102221 or terguride reduced the increments in lung water contents, grading of lung fibrosis, lung tumor necrosis factor-alpha (TNF-α), transforming growth factor-beta1 (TGF- β1 ) and vascular endothelial growth factor (VEGF) levels in lung injury and fibrosis-induced by bleomycin. Moreover, collagen content and myofibroblasts-alpha smooth muscle actin (α-SМA) were significantly decreased. Additionally, the simultaneous administration of RS-102221 with terguride had a synergistic outcome compared to that obtained by individual monotherapy. These findings suggested the potential use of 5-HT2A/B/C antagonists as anti-fibrotic agents in lung fibrosis. Copyright © 2016. Published by Elsevier Urban & Partner Sp. z o.o.

  8. Endothelin receptor A blockade reduces proteinuria and vascular hypertrophy in spontaneously hypertensive rats on high-salt diet in a blood-pressure-independent manner. (United States)

    Trenkner, Jörg; Priem, Friedrich; Bauer, Christian; Neumayer, Hans-Hellmut; Raschak, Manfred; Hocher, Berthold


    The renal endothelin (ET) system is involved in the pathogenesis of kidney fibrosis as well as blood pressure control by regulating tubular sodium excretion. Long-term effects of ETA receptor blockade on blood pressure and kidney function in spontaneously hypertensive rats (SHRs) on a high-salt diet are unknown. We treated SHRs on a 6% (w/v) NaCl sodium diet (SHR-S) for 48 weeks with the ETA antagonist LU 135252 (whose selectivity for ETA is 150 times greater than for ETB) with 10, 30 and 100 mg x kg(-1) x day(-1) or placebo. The ETA antagonist had at no time-point any effect on blood pressure. Glomerular filtration rate was normal in SHR-S and not altered by LU 135252. However, urinary albumin excretion was markedly reduced by the ETA antagonist (SHR-S, 145+/-50 mg/day; SHR-S+10 mg x kg(-1) x day(-1) LU 135252, 33+/-11 mg/day, Pproteinuria-induced chronic renal failure.

  9. Blockade of A2b Adenosine Receptor Reduces Tumor Growth and Immune Suppression Mediated by Myeloid-Derived Suppressor Cells in a Mouse Model of Melanoma

    Directory of Open Access Journals (Sweden)

    Raffaella Iannone


    Full Text Available The A2b receptor (A2bR belongs to the adenosine receptor family. Emerging evidence suggest that A2bR is implicated in tumor progression in some murine tumor models, but the therapeutic potential of targeting A2bR in melanoma has not been examined. This study first shows that melanoma-bearing mice treated with Bay 60-6583, a selective A2bR agonist, had increased melanoma growth. This effect was associated with higher levels of immune regulatory mediators interleukin-10 (IL-10 and monocyte chemoattractant protein 1 (MCP-1 and accumulation of tumor-associated CD11b positive Gr1 positive cells (CD11b+Gr1+ myeloid-derived suppressor cells (MDSCs. Depletion of CD11b+Gr1+ cells completely reversed the protumor activity of Bay 60-6583. Conversely, pharmacological blockade of A2bR with PSB1115 reversed immune suppression in the tumor microenvironment, leading to a significant melanoma growth delay. PSB1115 treatment reduced both levels of IL-10 and MCP-1 and CD11b+Gr1+ cell number in melanoma lesions. These effects were associated with higher frequency of tumor-infiltrating CD8 positive (CD8+ T cells and natural killer T (NKT cells and increased levels of T helper 1 (Th1-like cytokines. Adoptive transfer of CD11b+Gr1+ cells abrogated the antitumor activity of PSB1115. These data suggest that the antitumor activity of PSB1115 relies on its ability to lower accumulation of tumor-infiltrating MDSCs and restore an efficient antitumor T cell response. The antitumor effect of PSB1115 was not observed in melanoma-bearing nude mice. Furthermore, PSB1115 enhanced the antitumor efficacy of dacarbazine. These data indicate that A2bR antagonists such as PSB1115 should be investigated as adjuvants in the treatment of melanoma.

  10. Effects of the AT1 receptor antagonist on adhesion molecule expression in leukocytes and brain microvessels of stroke-prone spontaneously hypertensive rats. (United States)

    Takemori, K; Ito, H; Suzuki, T


    To elucidate the possible involvement of angiotensin II (AII) in the pathogenesis of microvascular changes in severe hypertension, we investigated the effects of angiotensin II type 1 (AT1) receptor antagonist and angiotensin-converting enzyme inhibitor (ACEI) on the expression of adhesion molecules of leukocytes and brain microvessels. Male stroke-prone spontaneously hypertensive rats (SHRSP) at 19 weeks of age were divided into three groups and age-matched Wistar-Kyoto rats (WKY) were used as the control group. AT1 receptor antagonist (TCV-116, 0.5 mg/kg/day) and ACEI (captopril, 20 mg/kg/day) were administered to SHRSP for 4 weeks. Mac-1 expression in leukocytes was investigated by flow cytometric analysis. For endothelial cells, we examined the expression of intercellular adhesion molecule-1 (ICAM-1), the AT1 receptor, and glucose transporter-1 (GLUT-1, a marker of the blood-brain barrier) using reverse transcription-polymerase chain reaction (RT-PCR). The blood pressure of AT1 receptor antagonist and ACEI-treated groups was slightly lower than that of the control, but was still greater than 220 mm Hg. Mac-1 expression, as well as ICAM-1 expression, was higher in control SHRSP than in WKY. Such enhanced expression of adhesion molecules in SHRSP was ameliorated by the administration of AT1 receptor antagonist or ACEI, the former being more effective. AT1 receptor expression was higher in control SHRSP than in WKY, and was lower in the AT1 receptor antagonist group, whereas no difference was found in the ACEI group. No significant differences were found in GLUT-1 expression among all groups. In the case of hypertensive cerebral injuries in SHRSP, leukocytes may have an important role for initiation via adhesion to endothelial cells. AT1 receptor antagonist showed a beneficial effect for the amelioration of enhanced expression of adhesion molecule in both leukocytes and endothelial cells. Thus, AII seems to be an important mediator for the hypertensive

  11. Increased expression of endothelin ET(B) and angiotensin AT(1) receptors in peripheral resistance arteries of patients with suspected acute coronary syndrome

    DEFF Research Database (Denmark)

    Dimitrijevic, Ivan; Ekelund, Ulf; Edvinsson, Marie-Louise


    of arterial vasoconstrictor endothelin (ET) and angiotensin (AT) receptors. Our aim was to investigate if the arterial expressions of these receptors are changed in patients with suspected but ruled out acute coronary syndrome (ACS). Small subcutaneous arteries (diameter of 100 microm) were surgically removed......Patients who experience chest pain, in which ischemic heart disease has been ruled out, still have an increased risk of future ischemic cardiac events and premature death, possibly due to subclinical endothelial dysfunction. A feature of endothelial dysfunction is an increased expression...... group. There were no significant differences in AT(2) and ET(A) receptor expression between the groups. The results indicate that the expression of arterial smooth muscle ET(B) and AT(1) receptors are increased in patients with suspected but ruled out ACS. These receptor changes could be important...

  12. Inverse agonism at the P2Y12 receptor and ENT1 transporter blockade contribute to platelet inhibition by ticagrelor. (United States)

    Aungraheeta, Riyaad; Conibear, Alexandra; Butler, Mark; Kelly, Eamonn; Nylander, Sven; Mumford, Andrew; Mundell, Stuart J


    Ticagrelor is a potent antagonist of the P2Y12 receptor (P2Y12R) and consequently an inhibitor of platelet activity effective in the treatment of atherothrombosis. Here, we sought to further characterize its molecular mechanism of action. Initial studies showed that ticagrelor promoted a greater inhibition of adenosine 5'-diphosphate (ADP)-induced Ca(2+) release in washed platelets vs other P2Y12R antagonists. This additional effect of ticagrelor beyond P2Y12R antagonism was in part as a consequence of ticagrelor inhibiting the equilibrative nucleoside transporter 1 (ENT1) on platelets, leading to accumulation of extracellular adenosine and activation of Gs-coupled adenosine A2A receptors. This contributed to an increase in basal cyclic adenosine monophosphate (cAMP) and vasodilator-stimulated phosphoprotein phosphorylation (VASP-P). In addition, ticagrelor increased platelet cAMP and VASP-P in the absence of ADP in an adenosine receptor-independent manner. We hypothesized that this increase originated from a direct effect on basal agonist-independent P2Y12R signaling, and this was validated in 1321N1 cells stably transfected with human P2Y12R. In these cells, ticagrelor blocked the constitutive agonist-independent activity of the P2Y12R, limiting basal Gi-coupled signaling and thereby increasing cAMP levels. These data suggest that ticagrelor has the pharmacological profile of an inverse agonist. Based on our results showing insurmountable inhibition of ADP-induced Ca(2+) release and forskolin-induced cAMP, the mode of antagonism of ticagrelor also appears noncompetitive, at least functionally. In summary, our studies describe 2 novel modes of action of ticagrelor, inhibition of platelet ENT1 and inverse agonism at the P2Y12R that contribute to its effective inhibition of platelet activation. © 2016 by The American Society of Hematology.

  13. PCP-induced alterations in cerebral glucose utilization in rat brain: blockade by metaphit, a PCP-receptor-acylating agent

    Energy Technology Data Exchange (ETDEWEB)

    Tamminga, C.A.; Tanimoto, K.; Kuo, S.; Chase, T.N.; Contreras, P.C.; Rice, K.C.; Jackson, A.E.; O' Donohue, T.L.


    The effects of phencyclidine (PCP) on regional cerebral glucose utilization was determined by using quantitative autoradiography with (/sup 14/C)-2-deoxyglucose. PCP increased brain metabolism in selected areas of cortex, particularly limbic, and in the basal ganglia and thalamus, whereas the drug decreased metabolism in areas related to audition. These results are consistent with the known physiology of central PCP neurons and may help to suggest brain areas involved in PCP-mediated actions. Moreover, based on the behavioral similarities between PCP psychosis and an acute schizophrenic episode, these data may be relevant to the understanding of schizophrenia. The PCP-receptor-acylating agent, metaphit, blocked most of these PCP actions. In addition, metaphit by itself was found to diminish glucose utilization rather uniformly throughout brain. These results indicate an antagonist effect of metaphit on the PCP system and suggest a widespread action of metaphit, putatively at a PCP-related site, possibly in connection with the N-methyl-D-aspartate (NMDA) receptor.

  14. Current status of chimeric antigen receptor engineered T cell-based and immune checkpoint blockade-based cancer immunotherapies. (United States)

    Hegde, Upendra P; Mukherji, Bijay


    Adoptive cell therapies with chimeric antigen receptor (CAR) engineered T cells (CAR-T) and immune checkpoint inhibition (ICI)-based cancer immunotherapies have lately shown remarkable success in certain tumor types. CAR-T cell-based therapies targeting CD19 can now induce durable remissions as well as prolong disease-free survival of patients with CD19 positive treatment refractory B cell malignancies and ICI-based therapies with humanized monoclonal antibodies against the T cell inhibitory receptors CTLA-4 and PD-1 as well as against the PD-1 ligand, PD-L1, can now achieve durable remissions as well as prolongation of life of a sizeable fraction of patients with melanoma and Hodgkin's lymphoma and non-small cell cancers. Most importantly, these immuno-therapeutic treatment modalities have raised the possibility of achieving long-term "containment" as well as "cures" for certain types of cancer. While this represents major advances in cancer immunotherapy, both modalities come with considerable toxicities, including fatalities. Although more work will be needed to bring CAR-T cell-based therapies to the bedside for most major cancers and a good deal more will be needed to make ICI-alone or in combination with other treatment modalities-work more consistently and across most major cancers, these two treatment modalities stand out as superb examples of successful translation of bench research to the bedside as well as represent real progress in the field of cancer immunotherapy.

  15. Pharmacological blockade of either, cannabinoid CB1 or CB2 receptors, prevents both cocaine-induced conditioned locomotion and cocaine-induced reduction of cell proliferation in the hippocampus of adult male rats.

    Directory of Open Access Journals (Sweden)



    Full Text Available Addiction to major drugs of abuse such as cocaine has been recently linked to alterations on adult neurogenesis in the hippocampus. The endogenous cannabinoid system modulated this proliferative response since pharmacological activation/blockade of cannabinoid CB1 and CB2 receptors by modulating not only neurogenesis but also cell death in the brain. In the present study, we evaluated whether the endogenous cannabinoid system affects cocaine-induced alterations in cell proliferation . To this end we examined if pharmacological blockade of either CB1 (Rimonabant, 3 mg/kg or CB2 receptors (AM630, 3 mg/kg affects cell proliferation (labeled with BrdU, found in the subventricular zone (SVZ of the lateral ventricles and the dentate subgranular zone (SGZ. In addition, we measured cell apoptosis (monitored by the expression of cleaved caspase-3 and glial activation ( by analizing the expression of GFAP and Iba-1 in the striatum and hippocampus, during acute or repeated (4 days cocaine administration (20 mg/kg. Results showed that acute cocaine decreased the number of BrdU+ cells in SVZ and SGZ. In contrast, repeated cocaine reduced the number of BrdU+ cells in SVZ only. Both acute and repeated cocaine increased the number of cleaved caspase-3+, GFAP+ and Iba1+ cells in the hippocampus, an effect counteracted by AM630 or Rimonabant that increased the number of BrdU+, GFAP+ and Iba1+ cells in the hippocampus. These results indicate that changes on neurogenic, apoptotic and gliosis processes, which were produced as a consequence of repeated cocaine administration, were normalized by the pharmacological blockade of CB1 and CB2. The restoring effects of cannabinoid receptor blockade on hippocampal cell proliferation were associated with a prevention of the induction of conditioned locomotion, but not of cocaine-induced sensitization.

  16. Alpha adrenergic receptor blockade increases capillarisation and fractional O2 extraction and lowers blood flow in contracting human skeletal muscle

    DEFF Research Database (Denmark)

    Mortensen, Stefan Peter; Egginton, Stuart; Madsen, Mads


    AIM: To investigate the effect of elevated basal shear stress on angiogenesis in humans, and the role of enhanced skeletal muscle capillarisation on blood flow and O2 extraction. METHODS: Limb haemodynamics and O2 extraction was measured at rest and during one-leg knee-extensor exercise (12 and 24W....... CONCLUSIONS: These results demonstrate that daily treatment with an α-adrenergic receptor blocker induces capillary growth in human skeletal muscle, likely due to increased shear stress. The increase in capillarisation resulted in an increased fractional O2 extraction, a lower blood flow and venous lactate...... basal capillary-to-fibre ratio was 1.69±0.08 and increased to 1.90±0.08 after treatment (Plower (6-7%; P

  17. Effects of local alpha2-adrenergic receptor blockade on adipose tissue lipolysis during prolonged systemic adrenaline infusion in normal man

    DEFF Research Database (Denmark)

    Simonsen, Lene; Enevoldsen, Lotte H; Stallknecht, Bente


    During prolonged adrenaline infusion, lipolysis peaks within 30 min and thereafter tends to decline, and we hypothesized that the stimulation of local adipose tissue alpha2-adrenergic receptors accounts for this decline. The lipolytic effect of a prolonged intravenous adrenaline infusion combined...... with local infusion of the alpha2-blocker phentolamine in superficial and deep abdominal subcutaneous adipose tissue and in preperitoneal adipose tissue was studied in seven healthy subjects. The interstitial glycerol concentration in the three adipose tissue depots was measured by the microdialysis method....... Regional adipose tissue blood flow was measured by the (133)Xe clearance technique. Regional glycerol output (lipolytic rate) was calculated from these measurements and simultaneous measurements of arterial glycerol concentrations. Adrenaline infusion increased lipolysis in all three depots (data...

  18. Exposure to AT1 Receptor Autoantibodies during Pregnancy Increases Susceptibility of the Maternal Heart to Postpartum Ischemia-Reperfusion Injury in Rats

    Directory of Open Access Journals (Sweden)

    Hui-Ping Wang


    Full Text Available Epidemiological studies have demonstrated that women with a history of preeclampsia have a two-fold increased risk of developing cardiovascular diseases in later life. It is not known whether or not this risk is associated with angiotensin II receptor type 1 autoantibody (AT1-AA, an agonist acting via activation of AT1 receptor (AT1R, which is believed to be involved in the pathogenesis of preeclampsia. The objective of the present study was to confirm the hypothesis that AT1-AA exposure during pregnancy may change the maternal cardiac structure and increase the susceptibility of the postpartum heart to ischemia/reperfusion injury (IRI. In the present study, we first established a preeclampsia rat model by intravenous injection of AT1-AA extracted from the plasma of rats immunized with AT1R, observed the susceptibility of the postpartum maternal heart to IRI at 16 weeks postpartum using the Langendorff preparation, and examined the cardiac structure using light and transmission electron microscopy. The modeled animals presented with symptoms very similar to the clinical symptoms of human preeclampsia during pregnancy, including hypertension and proteinuria. The left ventricular weight (LVW and left ventricular mass index (LVMI in AT1-AA treatment group were significantly increased as compared with those of the control group (p < 0.01, although there was no significant difference in final weight between the two groups. AT1-AA acting on AT1R not only induced myocardial cell hypertrophy, mitochondrial swelling, cristae disorganization and collagen accumulation in the interstitium but affected the left ventricular (LV function and delayed recovery from IRI. In contrast, co-treatment with AT1-AA + losartan completely blocked AT1-AA-induced changes in cardiac structure and function. These data indicate that the presence of AT1-AA during pregnancy was strongly associated with the markers of LV geometry changes and remodeling, and increased the cardiac

  19. Contrasting effects of lithium chloride and CB1 receptor blockade on enduring changes in the valuation of reward.

    Directory of Open Access Journals (Sweden)

    Giovanni eHernandez


    Full Text Available When an organism has been trained to respond for a reward, its learned behavior can be characterized as goal-directed or habitual based on whether or not it is susceptible to reward devaluation. Here, we evaluated whether instrumental responding for brain stimulation reward (BSR can devalued using a paradigm traditionally used for natural rewards. Rats were trained to lever press for BSR. Subsequently, BSR was paired with either lithium chloride (LiCl, 5 mg/kg, i.p, a pro-emetic, or AM251, a CB1 receptor antagonist (3 mg/kg, i.p.. Pairings of BSR with these two compounds or their respective vehicle were performed in a novel environment so that only unconditional effects of BSR were affected by the pharmacological manipulations. Subsequently, in a probe test, all rats were returned in the drug-free state to the boxes where they had received training instrumental responding was reassessed in the absence of BSR delivery. LiCl produced enduring decreases in the number of responses during the test session, whereas AM251 had no effect. These results show that instrumental responding for BSR is susceptible to devaluation, in accord with the proposal that this behavior is supported at least in part by associations between the response and the rewarding outcome. Furthermore, they suggest that the reward modulation observed in studies involving the use of CB1 receptor antagonists arises from changes in the organism’s motivation rather than due to drug-induced changes in the intrinsic value of reward.

  20. Selective cannabinoid-1 receptor blockade benefits fatty acid and triglyceride metabolism significantly in weight-stable nonhuman primates. (United States)

    Vaidyanathan, Vidya; Bastarrachea, Raul A; Higgins, Paul B; Voruganti, V Saroja; Kamath, Subhash; DiPatrizio, Nicholas V; Piomelli, Daniele; Comuzzie, Anthony G; Parks, Elizabeth J


    The goal of this study was to determine whether administration of the CB₁ cannabinoid receptor antagonist rimonabant would alter fatty acid flux in nonhuman primates. Five adult baboons (Papio Sp) aged 12.1 ± 4.7 yr (body weight: 31.9 ± 2.1 kg) underwent repeated metabolic tests to determine fatty acid and TG flux before and after 7 wk of treatment with rimonabant (15 mg/day). Animals were fed ad libitum diets, and stable isotopes were administered via diet (d₃₁-tripalmitin) and intravenously (¹³C₄-palmitate, ¹³C₁-acetate). Plasma was collected in the fed and fasted states, and blood lipids were analyzed by GC-MS. DEXA was used to assess body composition and a hyperinsulinemic euglycemic clamp used to assess insulin-mediated glucose disposal. During the study, no changes were observed in food intake, body weight, plasma, and tissue endocannabinoid concentrations or the quantity of liver-TG fatty acids originating from de novo lipogenesis (19 ± 6 vs. 16 ± 5%, for pre- and posttreatment, respectively, P = 0.39). However, waist circumference was significantly reduced 4% in the treated animals (P acids used for TRL-TG synthesis (40 ± 3 vs. 23 ± 4%, P = 0.02) and a twofold increase in TRL-TG turnover (1.5 ± 0.9 vs. 3.1 ± 1.4 μmol·kg⁻¹·h⁻¹, P = 0.03). These data support the potential for a strong effect of CB₁ receptor antagonism at the level of adipose tissue, resulting in improvements in fasting turnover of fatty acids at the whole body level, central adipose storage, and significant improvements in glucose homeostasis.

  1. Blockade of ATP P2X7 receptor enhances ischiatic nerve regeneration in mice following a crush injury. (United States)

    Ribeiro, Tatianne; Oliveira, Júlia Teixeira; Almeida, Fernanda Martins; Tomaz, Marcelo Amorim; Melo, Paulo A; Marques, Suelen Adriani; de Andrade, Geanne Matos; Martinez, Ana Maria Blanco


    Preventing damage caused by nerve degeneration is a great challenge. There is a growing body of evidence implicating extracellular nucleotides and their P2 receptors in many pathophysiological mechanisms. In this work we aimed to investigate the effects of the administration of Brilliant Blue G (BBG) and Pyridoxalphosphate-6-azophenyl-2', 4'- disulphonic acid (PPADS), P2X7 and P2 non-selective receptor antagonists, respectively, on sciatic nerve regeneration. Four groups of mice that underwent nerve crush lesion were used: two control groups treated with vehicle (saline), a group treated with BBG and a group treated with PPADS during 28days. Gastrocnemius muscle weight was evaluated. For functional evaluation we used the Sciatic Functional Index (SFI) and the horizontal ladder walking test. Nerves, dorsal root ganglia and spinal cords were processed for light and electron microscopy. Antinoceptive effects of BBG and PPADS were evaluated through von Frey E, and the levels of IL-1β and TNF-α were analyzed by ELISA. BBG promoted an increase in the number of myelinated fibers and on axon, fiber and myelin areas. BBG and PPADS led to an increase of TNF-α and IL-1β in the nerve on day 1 and PPADS caused a decrease of IL-1β on day 7. Mechanical allodynia was reversed on day 7 in the groups treated with BBG and PPADS. We concluded that BBG promoted a better morphological regeneration after ischiatic crush injury, but this was not followed by anticipation of functional improvement. In addition, both PPADS and BBG presented anti-inflammatory as well as antinociceptive effects. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Pharmacological blockade of the cold receptor TRPM8 attenuates autonomic and behavioral cold defenses and decreases deep body temperature (United States)

    Almeida, M. Camila; Hew-Butler, Tamara; Soriano, Renato N.; Rao, Sara; Wang, Weiya; Wang, Judy; Tamayo, Nuria; Oliveira, Daniela L.; Nucci, Tatiane B.; Aryal, Prafulla; Garami, Andras; Bautista, Diana; Gavva, Narender R.; Romanovsky, Andrej A.


    We studied M8-B, a selective and potent antagonist of the transient receptor potential melastatin-8 (TRPM8) channel. In vitro, M8-B blocked cold-induced and TRPM8-agonist-induced activation of rat, human, and murine TRPM8 channels, including those on primary sensory neurons. In vivo, M8-B decreased deep body temperature (Tb) in Trpm8+/+ mice and rats, but not in Trpm8−/− mice, thus suggesting an on-target action. The intravenous administration of M8-B was more effective in decreasing Tb in rats than the intrathecal or intracerebroventricular administration, indicating a peripheral action. M8-B attenuated cold-induced c-Fos expression in the lateral parabrachial nucleus, thus indicating a site of action within the cutaneous cooling neural pathway to thermoeffectors, presumably on sensory neurons. A low intravenous dose of M8-B did not affect Tb at either a constantly high or a constantly low ambient temperature (Ta), but the same dose readily decreased Tb if rats were kept at a high Ta during the M8-B infusion and transferred to a low Ta immediately thereafter. These data suggest that both a successful delivery of M8-B to the skin (high cutaneous perfusion) and the activation of cutaneous TRPM8 channels (by cold) are required for the hypothermic action of M8-B. At tail skin temperatures cold) activation of TRPM8. M8-B affected all thermoeffectors studied (thermopreferendum, tail skin vasoconstriction, and brown fat thermogenesis), thus suggesting that TRPM8 is a universal cold receptor in the thermoregulation system. PMID:22323721

  3. Involvement of prelimbic medial prefrontal cortex in panic-like elaborated defensive behaviour and innate fear-induced antinociception elicited by GABAA receptor blockade in the dorsomedial and ventromedial hypothalamic nuclei: role of the endocannabinoid CB1 receptor. (United States)

    Freitas, Renato Leonardo de; Salgado-Rohner, Carlos José; Hallak, Jaime Eduardo Cecílio; Crippa, José Alexandre de Souza; Coimbra, Norberto Cysne


    It has been shown that GABAA receptor blockade in the dorsomedial and ventromedial hypothalamic nuclei (DMH and VMH, respectively) induces elaborated defensive behavioural responses accompanied by antinociception, which has been utilized as an experimental model of panic attack. Furthermore, the prelimbic (PL) division of the medial prefrontal cortex (MPFC) has been related to emotional reactions and the processing of nociceptive information. The aim of the present study was to investigate the possible involvement of the PL cortex and the participation of local cannabinoid CB1 receptors in the elaboration of panic-like reactions and in innate fear-induced antinociception. Elaborated fear-induced responses were analysed during a 10-min period in an open-field test arena. Microinjection of the GABAA receptor antagonist bicuculline into the DMH/VMH evoked panic-like behaviour and fear-induced antinociception, which was decreased by microinjection of the non-selective synaptic contact blocker cobalt chloride in the PL cortex. Moreover, microinjection of AM251 (25, 100 or 400 pmol), an endocannabinoid CB1 receptor antagonist, into the PL cortex also attenuated the defensive behavioural responses and the antinociception that follows innate fear behaviour elaborated by DMH/VMH. These data suggest that the PL cortex plays an important role in the organization of elaborated forward escape behaviour and that this cortical area is also involved in the elaboration of innate fear-induced antinociception. Additionally, CB1 receptors in the PL cortex modulate both panic-like behaviours and fear-induced antinociception elicited by disinhibition of the DMH/VMH through microinjection of bicuculline.

  4. Increased perfusion pressure enhances the expression of endothelin (ETB) and angiotensin II (AT1, AT2) receptors in rat mesenteric artery smooth muscle cells

    DEFF Research Database (Denmark)

    Lindstedt, Isak; Xu, Cang-Bao; Zhang, Yaping


    In the present study, we hypothesized that changes in perfusion pressure result in altered expression of mRNA and protein encoding for the ETA-, ETB-, AT1- and AT2-receptors in rat mesenteric vessels. Segments of the rat mesenteric artery were cannulated with glass micropipettes, pressurized and ...

  5. The human angiotensin AT(1) receptor supports G protein-independent extracellular signal-regulated kinase 1/2 activation and cellular proliferation

    DEFF Research Database (Denmark)

    Hansen, Jakob Lerche; Aplin, Mark; Hansen, Jonas Tind


    The angiotensin AT(1) receptor is a key regulator of blood pressure and body fluid homeostasis, and it plays a key role in the pathophysiology of several cardiovascular diseases such as hypertension, cardiac hypertrophy, congestive heart failure, and arrhythmia. The importance of human angiotensin...

  6. Blockade of cannabinoid CB1 receptors improves renal function, metabolic profile, and increased survival of obese Zucker rats. (United States)

    Janiak, P; Poirier, B; Bidouard, J-P; Cadrouvele, C; Pierre, F; Gouraud, L; Barbosa, I; Dedio, J; Maffrand, J-P; Le Fur, G; O'Connor, S; Herbert, J-M


    Obesity is a major risk factor in the development of chronic renal failure. Rimonabant, a cannabinoid CB1 receptor antagonist, improves body weight and metabolic disorders; however, its effect on mortality and chronic renal failure associated with obesity is unknown. Obese Zucker rats received either rimonabant or vehicle for 12 months and were compared to a pair-fed but untreated group of obese rats. Mortality in the obese rats was significantly reduced by rimonabant along with a sustained decrease in body weight, transient reduction in food intake, and an increase in plasma adiponectin. This was associated with significant reduction in plasma total cholesterol, low-density lipoprotein cholesterol/high-density lipoprotein cholesterol ratio, triglycerides, glucose, norepinephrine, plasminogen activator inhibitor 1, and preservation of pancreatic weight and beta-cell mass index. The cannabinoid antagonist attenuated the increase in proteinuria, urinary N-acetylglucosaminidase excretion, plasma creatinine, and urea nitrogen levels while improving creatinine clearance. Renal hypertrophy along with glomerular and tubulointerstitial lesions were reduced by rimonabant. Although the drug did not modify hemodynamics, it normalized the pressor response to angiotensin II. Our study suggests that in a rat model of chronic renal failure due to obesity, rimonabant preserves renal function and increases survival.

  7. Enhancing Effects of NMDA-Receptor Blockade on Extinction Learning and Related Brain Activation Are Modulated by BMI (United States)

    Golisch, Anne; Heba, Stefanie; Glaubitz, Benjamin; Tegenthoff, Martin; Lissek, Silke


    A distributed network including prefrontal and hippocampal regions is involved in context-related extinction learning as well as in renewal. Renewal describes the recovery of an extinguished response if the context of extinction differs from the context of recall. Animal studies have demonstrated that prefrontal, but not hippocampal N-methyl-D-aspartate receptor (NMDAR) antagonism disrupted extinction learning and processing of task context. However, human studies of NMDAR in extinction learning are lacking, while NMDAR antagonism yielded contradictory results in other learning tasks. This fMRI study investigated the role of NMDAR for human behavioral and brain activation correlates of extinction and renewal. Healthy volunteers received a single dose of the NMDAR antagonist memantine prior to extinction of previously acquired stimulus-outcome associations presented in either identical or novel contexts. We observed better, and partly faster, extinction learning in participants receiving the NMDAR antagonist compared to placebo. However, memantine did not affect renewal. In both extinction and recall, the memantine group showed a deactivation in extinction-related brain regions, particularly in the prefrontal cortex, while hippocampal activity was increased. This higher hippocampal activation was in turn associated with the participants' body mass index (BMI) and extinction errors. Our results demonstrate potentially dose-related enhancing effects of memantine and highlight involvement of hippocampal NMDAR in context-related extinction learning. PMID:28326025

  8. Chronic stress increases experimental pancreatic cancer growth, reduces survival and can be antagonised by beta-adrenergic receptor blockade. (United States)

    Partecke, Lars Ivo; Speerforck, Sven; Käding, André; Seubert, Florian; Kühn, Sandra; Lorenz, Eric; Schwandke, Sebastian; Sendler, Matthias; Keßler, Wolfram; Trung, Dung Nguyen; Oswald, Stefan; Weiss, Frank Ulrich; Mayerle, Julia; Henkel, Christin; Menges, Pia; Beyer, Katharina; Lerch, Markus M; Heidecke, Claus-Dieter; von Bernstorff, Wolfram


    Chronic stress could promote tumour growth and reduce survival of pancreatic cancer patients via beta-adrenergic receptors of tumour cells. We have tested the impact of chronic acoustic and restraint stress on tumour development in an orthotopic syngeneic murine model of pancreatic cancer. Tumour-bearing C57BL/6 mice exposed to chronic stress had 45% (p = 0.0138) higher circulating steroid and 111% (p = 0.0052) higher adrenal tyrosine hydroxylase levels. Their immune response was significantly suppressed: The in vitro LPS response of splenocytes was significantly reduced regarding Th1- and Th2-cytokines including IFN-gamma, IL-6, IL-10 and MCP-1 (0.0011  0.05). TGF-beta in vitro was increased by 23.4% using catecholamines (p Beta-catecholamines increased proliferation in tumour cells by 18% (p beta-blocker propranolol reduced these effects by 25% (p beta-blockers of patients with pancreatic cancer or other malignancies should be further evaluated as an adjuvant anti-neoplastic agent in clinical trials. Copyright © 2016 IAP and EPC. Published by Elsevier B.V. All rights reserved.

  9. Post-acquisition hippocampal NMDA receptor blockade sustains retention of spatial reference memory in Morris water maze. (United States)

    Shinohara, Keisuke; Hata, Toshimichi


    Several studies have demonstrated that the hippocampal N-methyl-D-aspartate type glutamate receptors (NMDARs) are necessary for the acquisition but not the retention of spatial reference memory. In contrast, a few studies have shown that post-acquisition repetitive intraperitoneal injections of an NMDAR antagonist facilitate the retention of spatial reference memory in a radial maze task. In the present study, we investigated the role of hippocampal NMDARs in the retention of spatial reference memories in Morris water maze. In Experiment 1, 24 h after training (4 trials/day for 4 days), D-AP5 was chronically infused into the hippocampus of rats for 5 days. In the subsequent probe test (seven days after training), we found that rats infused with D-AP5 spent a significantly longer time in the target quadrant compared to chance level, whereas rats in the control group did not. In Experiment 2, D-AP5 was infused into the hippocampus 1 (immediate) or 7 (delayed) days after the training session. In the probe test, following the retention interval of 13 days, immediate infusion facilitated the performance in a manner similar to Experiment 1, whereas the delayed infusion did not. These findings suggest that hippocampal NMDARs play an important role in the deterioration of spatial reference memory. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. A neurocomputational account of catalepsy sensitization induced by D2 receptor blockade in rats: context dependency, extinction, and renewal. (United States)

    Wiecki, Thomas V; Riedinger, Katrin; von Ameln-Mayerhofer, Andreas; Schmidt, Werner J; Frank, Michael J


    Repeated haloperidol treatment in rodents results in a day-to-day intensification of catalepsy (i.e., sensitization). Prior experiments suggest that this sensitization is context-dependent and resistant to extinction training. The aim of this study was to provide a neurobiological mechanistic explanation for these findings. We use a neurocomputational model of the basal ganglia and simulate two alternative models based on the reward prediction error and novelty hypotheses of dopamine function. We also conducted a behavioral rat experiment to adjudicate between these models. Twenty male Sprague-Dawley rats were challenged with 0.25 mg/kg haloperidol across multiple days and were subsequently tested in either a familiar or novel context. Simulation results show that catalepsy sensitization, and its context dependency, can be explained by "NoGo" learning via simulated D2 receptor antagonism in striatopallidal neurons, leading to increasingly slowed response latencies. The model further exhibits a non-extinguishable component of catalepsy sensitization due to latent NoGo representations that are prevented from being expressed, and therefore from being unlearned, during extinction. In the rat experiment, context dependency effects were not dependent on the novelty of the context, ruling out the novelty model's account of context dependency. Simulations lend insight into potential complex mechanisms leading to context-dependent catalepsy sensitization, extinction, and renewal.

  11. Blockade of nicotinic and muscarinic receptors facilitates spontaneous migration of human peripheral granulocytes: failure in cystic fibrosis. (United States)

    Wessler, Ignaz; Neumann, Stefanie; Razen, Michael; Zepp, Fred; Kirkpatrick, Charles James


    Circulating leucocytes express muscarinic (m) and nicotinic (n) receptors and synthesize acetylcholine (ACh) regulating various cell functions. Leucocytes from patients with cystic fibrosis contain less ACh; therefore it was tested whether the regulation of cellular functions like migration differed from healthy volunteers. Peripheral blood (10-20 ml) was used, leucocytes were isolated by Ficoll® gradient and the commercial MIGRATEST® combined with flow cytometric analysis was applied (pore size 3 μm). In the absence of test substances 4900±1800 (n=10) leucocytes migrated within a time period of 2 h. In the presence of tubocurarine (TC, 30 μM) the cell number increased to 7500±2700 [n=10] corresponding to an increase of 162±20% (mean of individual experiments; pGranulocytes isolated from patients with cystic fibrosis did not respond (2h migration) to 30 μM TC (control: 5180±1400 cells [n=10]; TC: 5800±1400 [n=10]). Also in the presence of atropine (1 μM) and TC (30 μM) a significant effect was not detected (5800±1300 [n=10]). Auto-paracrine acetylcholine limits the migration of unstimulated peripheral granulocytes. This effect is impaired in cystic fibrosis most likely because of a reduced endogenous cholinergic tone. Copyright © 2012 Elsevier Inc. All rights reserved.

  12. Elevated N-terminal pro-brain natriuretic peptide levels predict an enhanced anti-hypertensive and anti-proteinuric benefit of dietary sodium restriction and diuretics, but not angiotensin receptor blockade, in proteinuric renal patients. (United States)

    Slagman, Maartje C J; Waanders, Femke; Vogt, Liffert; Damman, Kevin; Hemmelder, Marc; Navis, Gerjan; Laverman, Gozewijn D


    Renin-angiotensin aldosterone system (RAAS) blockade only partly reduces blood pressure, proteinuria and renal and cardiovascular risk in chronic kidney disease (CKD) but often requires sodium targeting [i.e. low sodium diet (LS) and/or diuretics] for optimal efficacy. However, both under- and overtitration of sodium targeting can easily occur. We evaluated whether N-terminal pro-brain natriuretic peptide (NT-proBNP), a biomarker of volume expansion, predicts the benefits of sodium targeting in CKD patients. In a cross-over randomized controlled trial, 33 non-diabetic CKD patients (proteinuria 3.8 ± 0.4 g/24 h, blood pressure 143/86 ± 3/2 mmHg, creatinine clearance 89 ± 5 mL/min) were treated during 6-week periods with placebo, angiotensin receptor blockade (ARB; losartan 100 mg/day) and ARB plus diuretics (losartan 100 mg/day plus hydrochlorothiazide 25 mg/day), combined with LS (93 ± 52 mmol Na(+)/24 h) and regular sodium diet (RS; 193 ± 62 mmol Na(+)/24 h, P diuretics and was normalized by ARB + diuretic + LS [39 (26-59) pg/mL, P = 0.65 versus controls]. NT-proBNP levels above the upper limit of normal (>125 pg/mL) predicted a larger reduction of blood pressure and proteinuria by LS and diuretics but not by ARB, during all steps of the titration regimen. Elevated NT-proBNP levels predict an enhanced anti-hypertensive and anti-proteinuric benefit of sodium targeting, but not RAAS blockade, in proteinuric CKD patients. Importantly, this applies to the untreated condition, as well as to the subsequent treatment steps, consisting of RAAS blockade and even RAAS blockade combined with diuretics. NT-proBNP can be a useful tool to identify CKD patients in whom sodium targeting can improve blood pressure and proteinuria.

  13. Increased expression of endothelin ET(B) and angiotensin AT(1) receptors in peripheral resistance arteries of patients with suspected acute coronary syndrome

    DEFF Research Database (Denmark)

    Dimitrijevic, Ivan; Ekelund, Ulf; Edvinsson, Lars


    in an abdominal biopsy from 12 patients suspicious of ACS (susp ACS), admitted to the medical telemetry unit for chest pain. The vessels were analyzed for their receptor protein expression by quantitative immunohistochemistry using specific antibodies directed against ET(A), ET(B), AT(1), and AT(2) receptors......Patients who experience chest pain, in which ischemic heart disease has been ruled out, still have an increased risk of future ischemic cardiac events and premature death, possibly due to subclinical endothelial dysfunction. A feature of endothelial dysfunction is an increased expression...... of arterial vasoconstrictor endothelin (ET) and angiotensin (AT) receptors. Our aim was to investigate if the arterial expressions of these receptors are changed in patients with suspected but ruled out acute coronary syndrome (ACS). Small subcutaneous arteries (diameter of 100 microm) were surgically removed...

  14. Use of Remifentanil in a Novel Clinical Paradigm to Characterize Onset and Duration of Opioid Blockade by Samidorphan, a Potent μ-Receptor Antagonist (United States)

    Shram, Megan J.; Silverman, Bernard; Ehrich, Elliot; Sellers, Edward M.; Turncliff, Ryan


    Abstract A novel clinical study design was used to evaluate the blockade of a selective short-acting μ-opioid agonist (remifentanil) in 24 opioid-experienced subjects. Samidorphan (3-carboxamido-4-hydroxynaltrexone) is a novel opioid modulator with μ-antagonist properties. Objective (pupil diameter) and subjective (visual analog scale) responses to repeated remifentanil and saline infusion challenges were assessed after single oral administration of placebo (day 1) and samidorphan (day 2). Complete blockade persisted with samidorphan for 24 hours for pupil miosis and 48 hours for the drug liking visual analog scale. Samidorphan effects persisted beyond measurable samidorphan exposure (t½ = 7 hours). Samidorphan was associated with complete blockade of remifentanil, and the duration supports daily administration. This study used a novel approach with multiple administrations of remifentanil to successfully demonstrate a durable effect with samidorphan and a rapid and potent blockade of physiological and subjective μ-opioid effects. PMID:25928699

  15. Antibodies against AT1 receptors are associated with vascular endothelial and smooth muscle function impairment: protective effects of hydroxysafflor yellow A.

    Directory of Open Access Journals (Sweden)

    Zhu Jin

    Full Text Available Ample evidence has shown that autoantibodies against AT1 receptors (AT1-AA are closely associated with human cardiovascular disease. The aim of this study was to investigate mechanisms underlying AT1-AA-induced vascular structural and functional impairments in the formation of hypertension, and explore ways for preventive treatment. We used synthetic peptide corresponding to the sequence of the second extracellular loop of the AT1 receptor (165-191 to immunize rats and establish an active immunization model. Part of the model received preventive therapy by losartan (20 mg/kg/day and hyroxysafflor yellow A (HSYA (10 mg/kg/day. The result show that systolic blood pressure (SBP and heart rate (HR of immunized rats was significantly higher, and closely correlated with the plasma AT1-Ab titer. The systolic response of thoracic aortic was increased, but diastolic effects were attenuated markedly. Histological observation showed that the thoracic aortic endothelium of the immunized rats became thinner or ruptured, inflammatory cell infiltration, medial smooth muscle cell proliferation and migration, the vascular wall became thicker. There was no significant difference in serum antibody titer between losartan and HSYA groups and the immunized group. The vascular structure and function were reversed, and plasma biochemical parameters were also improved significantly in the two treatment groups. These results suggest that AT1-Ab could induce injury to vascular endothelial cells, and proliferation of smooth muscle cells. These changes were involved in the formation of hypertension. Treatment with AT1 receptor antagonists and anti oxidative therapy could block the pathogenic effect of AT1-Ab on vascular endothelial and smooth muscle cells.

  16. Alpha-1-adrenergic receptor blockade modifies insulin-regulated aminopeptidase (IRAP) activity in rat prostate and modulates oxytocin functions. (United States)

    Saníger, Marcela Arrazola; Ramírez-Expósito, María Jesús; de la Chica, Susana; Carrera-González, María Pilar; Mayas, María Dolores; Manuel Martínez-Martos, José


    Oxytocin (OT) is one of the important paracrine factors that prostate synthesizes. OT maintains its resting tone and stimulates its contractile activity. However, the involvement of OT in modulating cell proliferation of the prostate is being investigated. In fact, alterations in OT concentrations accompany both benign prostatic hyperplasia/hypertrophy and carcinoma of the prostate. The enzyme Insulin-regulated aminopeptidase (IRAP) is the main responsible of OT levels regulation through its catabolism. To date, the long-acting selective α(1)-adrenergic receptor antagonist doxazosin is widely used to the treatment of BPH. Thus, our aim was to analyze the effects of doxazosin on IRAP specific activity and its putative effects on prostate OT regulation and functions. Fifteen male Wistar rats were treated subcutaneously with 10 mg/Kg doxazosin during 15 days and fifteen controls were treated with the vehicle only. After the treatment period, prostate was removed to obtain soluble and membrane-bound fractions. Soluble and membrane-bound IRAP specific activities were assayed fluorometrically using leucyl-ß-naphthylamide as substrate. Prostate OT content was assayed by enzyme immunoassay. Doxazosin treatment significantly increased membrane-bound IRAP specific activity in rat prostate by 59.4%, whereas no changes were observed in the soluble fraction. Treatment with doxazosin also significantly increased OT concentration by 26.3%. In vivo administration of doxazosin to male rats modify both prostatic IRAP activity and OT levels. Because there is now evidence that OT plays a physiological role in the regulation of growth and muscular contractility within the gland, more attention should be paid to IRAP activity, which could represent a new target for the regulation of the functions of OT under physiological or pathological conditions such as BPH and prostate cancer.

  17. Blockade of Toll-like receptor 2 prevents spontaneous cytokine release from rheumatoid arthritis ex vivo synovial explant cultures

    LENUS (Irish Health Repository)

    Nic An Ultaigh, Sinead


    Abstract Introduction The aim of this study was to examine the effect of blocking Toll-like receptor 2 (TLR2) in rheumatoid arthritis (RA) synovial cells. Methods RA synovial tissue biopsies, obtained under direct visualization at arthroscopy, were established as synovial explant cultures ex vivo or snap frozen for immunohistology. Mononuclear cell cultures were isolated from peripheral blood and synovial fluid of RA patients. Cultures were incubated with the TLR1\\/2 ligand, Pam3CSK4 (200 ng, 1 and 10 μg\\/ml), an anti-TLR2 antibody (OPN301, 1 μg\\/ml) or an immunoglobulin G (IgG) (1 μg\\/ml) matched control. The comparative effect of OPN301 and adalimumab (anti-tumour necrosis factor alpha) on spontaneous release of proinflammatory cytokines from RA synovial explants was determined using quantitative cytokine MSD multiplex assays or ELISA. OPN301 penetration into RA synovial tissue explants cultures was assessed by immunohistology. Results Pam3CSK4 significantly upregulated interleukin (IL)-6 and IL-8 in RA peripheral blood mononuclear cells (PBMCs), RA synovial fluid mononuclear cells (SFMCs) and RA synovial explant cultures (P < 0.05). OPN301 significantly decreased Pam3CSK4-induced cytokine production of tumour necrosis factor alpha (TNF-α), IL-1β, IL-6, interferon (IFN)-γ and IL-8 compared to IgG control in RA PBMCs and SFMCs cultures (all P < 0.05). OPN301 penetration of RA synovial tissue cultures was detected in the lining layer and perivascular regions. OPN301 significantly decreased spontaneous cytokine production of TNF-α, IL-1β, IFN-γ and IL-8 from RA synovial tissue explant cultures (all P < 0.05). Importantly, the inhibitory effect of OPN on spontaneous cytokine secretion was comparable to inhibition by anti-TNFα monoclonal antibody adalimumab. Conclusions These findings further support targeting TLR2 as a potential therapeutic agent for the treatment of RA.

  18. P2Y12 Receptor Blockade Augments Glycoprotein IIb‐IIIa Antagonist Inhibition of Platelet Activation, Aggregation, and Procoagulant Activity (United States)

    Berny‐Lang, Michelle A.; Jakubowski, Joseph A.; Sugidachi, Atsuhiro; Barnard, Marc R.; Michelson, Alan D.; Frelinger, Andrew L.


    Background New antiplatelet agents that provide greater, more consistent inhibition of the platelet ADP receptor P2Y12 may be used in combination with glycoprotein (GP) IIb‐IIIa antagonists, but their combined effect on platelet function and procoagulant activity is not well studied. Therefore, the objective of this study was to evaluate the independent and complementary effects of P2Y12 and GPIIb‐IIIa inhibition on platelet function and procoagulant activity. Methods and Results Healthy donor blood was treated with the active metabolite of prasugrel (R‐138727 5 μmol/L), GPIIb‐IIIa antagonists (abciximab 3 μg/mL or eptifibatide 0.9 μg/mL), and combinations thereof, exposed to physiologically relevant agonists (collagen and ADP) and then evaluated for markers of platelet activation and procoagulant activity. Significant interactions between R‐138727 and GPIIb‐IIIa antagonists were observed. R‐138727 and the GPIIb‐IIIa antagonists had additive inhibitory effects on collagen‐stimulated platelet aggregation and on the collagen plus ADP–stimulated level of activated platelet surface GPIIb‐IIIa. R‐138727 and abciximab each inhibited collagen plus ADP–stimulated platelet phosphatidylserine expression and prothrombin cleavage, and the combination produced greater inhibition than achieved with abciximab alone. In contrast, eptifibatide did not inhibit, but instead enhanced, collagen plus ADP–stimulated prothrombin cleavage. Addition of R‐138727 reduced prothrombin cleavage in eptifibatide‐treated samples, suggesting a novel mechanism for potential benefit from combined prasugrel and eptifibatide treatment. Conclusions The complementary effects of abciximab and R‐138727 on platelet activation, aggregation, and procoagulant activity suggest their combined use may, to a greater degree than with either agent alone, reduce thrombus formation in vivo. PMID:23676293

  19. Cell surface-bound TIMP3 induces apoptosis in mesenchymal Cal78 cells through ligand-independent activation of death receptor signaling and blockade of survival pathways.

    Directory of Open Access Journals (Sweden)

    Christina Koers-Wunrau

    exclusively cell surface-bound endogenous TIMP3 induces apoptosis in mesenchymal Cal78 cells through ligand-independent activation of death receptor signaling and blockade of survival signaling pathways.

  20. The ACE-2/Ang1-7/Mas cascade enhances bone structure and metabolism following angiotensin-II type 1 receptor blockade. (United States)

    Abuohashish, Hatem M; Ahmed, Mohammed M; Sabry, Dina; Khattab, Mahmoud M; Al-Rejaie, Salim S


    The renin angiotensin system (RAS) regulates numerous systemic functions and is expressed locally in skeletal tissues. Angiotensin1-7 (Ang1-7) is a beneficial member of the RAS, and the therapeutic effects of a large number of angiotensin receptors blockers (ARBs) are mediated by an Ang1-7-dependent cascade. This study examines whether the reported osteo-preservative effects of losartan are mediated through the angiotensin converting enzyme2 (ACE-2)/Ang1-7/Mas pathway in ovariectomized (OVX) rats. Sham and OVX animals received losartan (10mg/kg/d p.o.) for 6 weeks. A specific Mas receptor blocker (A-779) was delivered via mini-osmotic pumps during the losartan treatment period. Serum and urine bone metabolism biomarker levels were measured. Bone trabecular and cortical morphometry were quantified in distal femurs, whereas mineral contents were estimated in ashed bones, serum and urine. Finally, the expression of RAS components, the receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG) was determined. Losartan significantly improved the elevated bone metabolism marker levels and altered trabecular and cortical structures in OVX animals, and restored normal urinary and skeletal mineral levels. Mas receptor inhibition significantly abolished all osteo-protective effects of losartan and enhanced the deleterious effects of OVX. Losartan enhanced OVX-induced up-regulation of ACE-1, AngII, angiotensin type 1 (AT1) receptor and RANKL expression, and increased ACE-2, Ang1-7, Mas and OPG expression in OVX animals. However, A-779 significantly eradicated the effects of losartan on RAS components and RANKL/OPG expression. Thus, Ang1-7 are involved in the osteo-preservative effects of losartan via Mas receptor, which may add therapeutic value to this well-known antihypertensive agent. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Staphylococcal nuclease domain containing-1 (SND1 promotes migration and invasion via angiotensin II type 1 receptor (AT1R and TGFβ signaling

    Directory of Open Access Journals (Sweden)

    Prasanna K. Santhekadur


    Full Text Available Staphylococcal nuclease domain containing-1 (SND1 is overexpressed in human hepatocellular carcinoma (HCC patients and promotes tumorigenesis by human HCC cells. We now document that SND1 increases angiotensin II type 1 receptor (AT1R levels by increasing AT1R mRNA stability. This results in activation of ERK, Smad2 and subsequently the TGFβ signaling pathway, promoting epithelial–mesenchymal transition (EMT and migration and invasion by human HCC cells. A positive correlation was observed between SND1 and AT1R expression levels in human HCC patients. Small molecule inhibitors of SND1, alone or in combination with AT1R blockers, might be an effective therapeutic strategy for late-stage aggressive HCC.

  2. Angiotensin receptor blockade recovers hepatic UCP2 expression and aconitase and SDH activities and ameliorates hepatic oxidative damage in insulin resistant rats. (United States)

    Montez, Priscilla; Vázquez-Medina, José Pablo; Rodríguez, Rubén; Thorwald, Max A; Viscarra, José A; Lam, Lisa; Peti-Peterdi, Janos; Nakano, Daisuke; Nishiyama, Akira; Ortiz, Rudy M


    Metabolic syndrome (MetS) is commonly associated with elevated renin-angiotensin system, oxidative stress, and steatohepatitis with down-regulation of uncoupling proteins (UCPs). However, the mechanisms linking renin-angiotensin system, steatosis, and UCP2 to hepatic oxidative damage during insulin resistance are not described. To test the hypothesis that angiotensin receptor activation contributes to decreased hepatic UCP2 expression and aconitase activity and to increased oxidative damage after increased glucose intake in a model of MetS, lean and obese Long Evans rats (n = 10/group) were randomly assigned to the following groups: 1) untreated Long Evans Tokushima Otsuka (lean, strain control), 2) untreated Otsuka Long Evans Tokushima Fatty (OLETF) (MetS model), 3) OLETF + angiotensin receptor blocker (ARB) (10 mg olmesartan/kg·d × 6 wk), 4) OLETF + high glucose (HG) (5% in drinking water × 6 wk), and 5) OLETF + ARB + HG (ARB/HG × 6 wk). HG increased body mass (37%), plasma triglycerides (TGs) (35%), plasma glycerol (87%), plasma free fatty acids (28%), and hepatic nitrotyrosine (74%). ARB treatment in HG decreased body mass (12%), plasma TG (15%), plasma glycerol (23%), plasma free fatty acids (14%), and hepatic TG content (42%), suggesting that angiotensin receptor type 1 (AT1) activation and increased adiposity contribute to the development of obesity-related dyslipidemia. ARB in HG also decreased hepatic nitrotyrosine and increased hepatic UCP2 expression (59%) and aconitase activity (40%), as well as antioxidant enzyme activities (50-120%), suggesting that AT1 activation also contributes to protein oxidation, impaired lipid metabolism, and antioxidant metabolism in the liver. Thus, in addition to promoting obesity-related hypertension, AT1 activation may also impair lipid metabolism and antioxidant capacity, resulting in steatosis via decreased UCP2 and tricarboxylic acid cycle activity.

  3. Opposite control of mesocortical and mesoaccumbal dopamine pathways by serotonin2B receptor blockade: Involvement of medial prefrontal cortex serotonin1A receptors. (United States)

    Devroye, Céline; Haddjeri, Nasser; Cathala, Adeline; Rovera, Renaud; Drago, Filippo; Piazza, Pier Vincenzo; Artigas, Francesc; Spampinato, Umberto


    Recent studies have shown that serotonin2B receptor (5-HT2BR) antagonists exert opposite facilitatory and inhibitory effects on dopamine (DA) release in the medial prefrontal cortex (mPFC) and the nucleus accumbens (NAc), respectively, thereby leading to the proposal that these compounds could provide an interesting pharmacological tool for treating schizophrenia. Although the mechanisms underlying these effects remain unknown, several data in the literature suggest that 5-HT1ARs located into the mPFC could participate in this interaction. The present study, using in vivo microdialysis and electrophysiological recordings in rats, assessed this hypothesis by means of two selective 5-HT1AR (WAY 100635) and 5-HT2BR (RS 127445) antagonists. WAY 100635, administered either subcutaneously (0.16 mg/kg, s.c) or locally into the mPFC (0.1 μM), blocked the changes of mPFC and NAc DA release induced by the intraperitoneal administration of RS 127445 (0.16 mg/kg, i.p.). The administration of RS 127445 (0.16 mg/kg, i.p.) increased both dorsal raphe nucleus (DRN) 5-HT neuron firing rate and 5-HT outflow in the mPFC. Likewise, mPFC 5-HT outflow was increased following the intra-DRN injection of RS 127445 (0.032 μg/0.2 μl). Finally, intra-DRN injection of RS 127445 increased and decreased DA outflow in the mPFC and the NAc, respectively, these effects being reversed by the intra-mPFC perfusion of WAY 100635. These results demonstrate the existence of a functional interplay between mPFC 5-HT1ARs and DRN 5-HT2BRs in the control of the DA mesocorticolimbic system, and highlight the clinical interest of this interaction, as both receptors represent an important pharmacological target for the treatment of schizophrenia. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. High intraluminal pressure via H2O2 upregulates arteriolar constrictions to angiotensin II by increasing the functional availability of AT1 receptors (United States)

    Bagi, Zsolt; Erdei, Nora; Koller, Akos


    Previously, we found that high intraluminal pressure leads to production of reactive oxygen species (ROS) and also upregulates several components of the renin-angiotensin system in the wall of small arteries. We hypothesized that acute exposure of arterioles to high intraluminal pressure in vitro via increasing ROS production enhances the functional availability of type 1 angiotensin II (Ang II) receptors (AT1 receptors), resulting in sustained constrictions. In arterioles (∼180 μm) isolated from rat skeletal muscle, Ang II elicited dose-dependent constrictions, which decreased significantly by the second application [maximum (max.): from 59% ± 4% to 26% ± 5% at 10−8 M; P < 0.05] in the presence of 80 mmHg of intraluminal pressure. In contrast, if the arterioles were exposed to high intraluminal pressure (160 mmHg for 30 min), Ang II-induced constrictions remained substantial on the second application (max.: 51% ± 3% at 10−8 M). In the presence of Tiron and polyethylene glycol (PEG)-catalase, known to reduce the level of superoxide anion and hydrogen peroxide (H2O2), second applications of Ang II evoked similarly reduced constrictions, even after high-pressure exposure (29% ± 4% at 10−8 M). Furthermore, when arterioles were exposed to H2O2 (for 30 min, 10−7 M, at normal 80 mmHg pressure), Ang II-induced constrictions remained substantial on second applications (59% ± 5% at 10−8 M). These findings suggest that high pressure, likely via inducing H2O2 production, increases the functional availability of AT1 receptors and thus enhances Ang II-induced arteriolar constrictions. We propose that in hypertension–regardless of etiology–high intraluminal pressure, via oxidative stress, enhances the functional availability of AT1 receptors augmenting Ang II-induced constrictions. PMID:18567710

  5. Angiotensin II type 1 receptor (AT-1R) expression correlates with VEGF-A and VEGF-D expression in invasive ductal breast cancer. (United States)

    Jethon, Aleksandra; Pula, Bartosz; Piotrowska, Aleksandra; Wojnar, Andrzej; Rys, Janusz; Dziegiel, Piotr; Podhorska-Okolow, Marzena


    Recent studies point to the involvement of angiotensin II (Ang II) receptor type 1 (AT-1R) on processes of metastasing, stimulation of invasiveness and angiogenesis in tumours. In this study, the correlation between intensity of AT-1R expression and expression of lymph- and angiogenesis markers in invasive ductal breast cancers (IDC) was examined. Immunohistochemical studies (IHC) were performed on archival material of 102 IDC cases. Only 28 (27.5%) cases manifested low AT-1R expression while 74 (72.5%) cases demonstrated a moderate or pronounced AT-1R expression. Expression intensity of AT-1R was found to correlate with expressions of VEGF-A (r = 0.26; p = 0.008) and VEGF-D (r = 0.24; p = 0.015). Out of the examined markers of angiogenesis and lymphangiogenesis only the pronounced expression of VEGF-C was found to correlate with patient poor clinical outcome (p = 0.009). The positive correlation between AT-1R and VEGF-A and VEGF-D could point to stimulatory action of Ang II on their expression what might result in augmented lymph- and angiogenesis in IDC.

  6. Effects of the AT1 receptor blocker candesartan on myocardial ischemia/reperfusion in isolated rat hearts. (United States)

    Songur, C Murat; Songur, Merve Ozenen; Kocabeyoglu, Sinan Sabit; Basgut, Bilgen


    We sought to investigate the effects of the angiotension II receptor blocker candesartan on ischemia-reperfusion injury using a cardioplegia arrested isolated rat heart model. Ischemia-reperfusion injury was induced in isolated rat hearts with 40 minutes of global ischemia followed by a 30-minute reperfusion protocol. Throughout the experiment, constant pressure perfusion was achieved using a Langendorff apparatus. Cardioplegic solution alone, and in combination with candesartan, was administered before ischemia and 20 minutes after ischemia. Post-ischemic recovery of contractile function, left ventricular developed pressure, left ventricular end-diastolic pressure and contraction and relaxation rates were evaluated. In the control group, left ventricular developed pressure, rate pressure product, contraction and relaxation rates and coronary flow significantly decreased but coronary resistance increased following reperfusion. With the administration of candesartan alone, parameters did not differ compared to controls. Contractile parameters improved in the group that received candesartan in combination with the cardioplegia compared to the group that received cardioplegia alone; however, the difference between these two groups was insignificant. In this study, the addition of candesartan to a cardioplegic arrest protocol routinely performed during cardiac surgery did not provide a significant advantage in protection against ischemia-reperfusion injury compared with the administration of cardioplegic solution alone.

  7. AT1 receptor antagonist induces thermogenic beige adipocytes in the inguinal white adipose tissue of obese mice. (United States)

    Graus-Nunes, Francielle; Rachid, Tamiris Lima; de Oliveira Santos, Felipe; Barbosa-da-Silva, Sandra; Souza-Mello, Vanessa


    To evaluate whether losartan is able to induce beige adipocytes formation, focusing on the thermogenic gene expression and adipocyte remodeling in the subcutaneous white adipose tissue of diet-induced obese mice. Male C57BL/6 mice received a control diet (10% energy as lipids) or a high-fat diet (50% energy as lipids) for 10 weeks, followed by a 5-week treatment with losartan: control group, control-losartan group (10 mg/Kg/day), high-fat group and high-fat-losartan group (10 mg/Kg/day). Biochemical, morphometrical, stereological and molecular approaches were used to evaluate the outcomes. The high-fat diet elicited overweight, insulin resistance and adipocyte hypertrophy in the high-fat group, all of which losartan rescued in the high-fat-losartan group. These effects comply with the induction of beige adipocytes within the inguinal fat pads in high-fat-losartan group as they exhibited the greatest energy expenditure among the groups along with the presence uncoupling protein 1 positive multilocular adipocytes with enhanced peroxisome proliferator-activated receptor gamma coactivator 1-alpha and PR domain containing 16 mRNA levels, indicating a significant potential for mitochondrial biogenesis and adaptive thermogenesis. Our results show compelling evidence that losartan countered diet-induced obesity in mice by enhancing energy expenditure through beige adipocytes induction. Reduced body mass, increased insulin sensitivity, decreased adipocyte size and marked expression of uncoupling protein 1 by ectopic multilocular adipocytes support these findings. The use of losartan as a coadjutant medicine to tackle obesity and its related disorders merits further investigation.

  8. Synthesis, anti-hypertensive effect of a novel angiotensin II AT1 receptor antagonist and its anti-tumor activity in prostate cancer. (United States)

    Da, Y-J; Yuan, W-D; Zhu, L-F; Chen, Z-L


    Since the first non-peptide Ang II receptor antagonist was originally reported, it has become the most common target in the development of new treatments for hypertension. In recent years, all components of the classical RAS have been reported in the prostate, these results suggest the possibility that ARB is a novel therapeutic class of agents for prostate cancer. In this study, a new compound 2-(4-((2-propyl-5-nitro-1H-benzo[d]imidazol-1-yl) methyl)-1H-indol-1-yl) benzoic acid was synthesized and evaluated as a novel angiotensin II AT1 receptor antagonist by radioligand binding assays, anti-hypertensive assays in vivo and oral acute toxicity test. MTT assays and tests in nude mice were used to demonstrate its anti-tumor activity. This new compound showed high affinity to AT1 receptor and anti-hypertensive activity in spontaneously hypertensive rats and renal hypertensive rats. Moreover, in human prostate cancer cells and in athymic nude mice bearing human prostate cancer cells, we observed this new compound had an efficient antiproliferative activity in vitro and anti-tumor activity in vivo. The preliminary pharmacological characteristics with oral acute toxicity test suggested that this new compound can be considered as a candidate for both anti-hypertensive and anti-tumor drug. © Georg Thieme Verlag KG Stuttgart · New York.

  9. Pharmacological blockade of either cannabinoid CB1 or CB2 receptors prevents both cocaine-induced conditioned locomotion and cocaine-induced reduction of cell proliferation in the hippocampus of adult male rat (United States)

    Blanco-Calvo, Eduardo; Rivera, Patricia; Arrabal, Sergio; Vargas, Antonio; Pavón, Francisco Javier; Serrano, Antonia; Castilla-Ortega, Estela; Galeano, Pablo; Rubio, Leticia; Suárez, Juan; Rodriguez de Fonseca, Fernando


    Addiction to major drugs of abuse, such as cocaine, has recently been linked to alterations in adult neurogenesis in the hippocampus. The endogenous cannabinoid system modulates this proliferative response as demonstrated by the finding that pharmacological activation/blockade of cannabinoid CB1 and CB2 receptors not only modulates neurogenesis but also modulates cell death in the brain. In the present study, we evaluated whether the endogenous cannabinoid system affects cocaine-induced alterations in cell proliferation. To this end, we examined whether pharmacological blockade of either CB1 (Rimonabant, 3 mg/kg) or CB2 receptors (AM630, 3 mg/kg) would affect cell proliferation [the cells were labeled with 5-bromo-2′-deoxyuridine (BrdU)] in the subventricular zone (SVZ) of the lateral ventricle and the dentate subgranular zone (SGZ). Additionally, we measured cell apoptosis (as monitored by the expression of cleaved caspase-3) and glial activation [by analyzing the expression of glial fibrillary acidic protein (GFAP) and Iba-1] in the striatum and hippocampus during acute and repeated (4 days) cocaine administration (20 mg/kg). The results showed that acute cocaine exposure decreased the number of BrdU-immunoreactive (ir) cells in the SVZ and SGZ. In contrast, repeated cocaine exposure reduced the number of BrdU-ir cells only in the SVZ. Both acute and repeated cocaine exposure increased the number of cleaved caspase-3-, GFAP- and Iba1-ir cells in the hippocampus, and this effect was counteracted by AM630 or Rimonabant, which increased the number of BrdU-, GFAP-, and Iba1-ir cells in the hippocampus. These results indicate that the changes in neurogenic, apoptotic and gliotic processes that were produced by repeated cocaine administration were normalized by pharmacological blockade of CB1 and CB2. The restorative effects of cannabinoid receptor blockade on hippocampal cell proliferation were associated with the prevention of the induction of conditioned

  10. Evaluation of [(11)C]methyl-losartan and [(11)C]methyl-EXP3174 for PET imaging of renal AT1receptor in rats. (United States)

    Ismail, Basma; Hadizad, Tayebeh; Antoun, Rawad; Lortie, Mireille; deKemp, Robert A; Beanlands, Rob S B; DaSilva, Jean N


    The angiotensin II type 1 receptor (AT1R) is responsible for the main effects of the renin-angiotensin system (RAS), and its expression pattern is altered in several diseases. The [(11)C]methylated derivatives of the clinically used AT1R blocker (ARB) losartan and its active metabolite EXP3174, that binds with higher affinity to AT1R, were evaluated as potential PET imaging tracers in rat kidneys. [(11)C]Methyl-losartan and [(11)C]methyl-EXP3174 were synthesized by [(11)C]methylation of the tetrazole-protected analogs using [11C]methyl iodide. Tissue uptake and binding selectivity of [(11)C]methyl-losartan were assessed by ex-vivo biodistribution and in-vitro autoradiography. Radiolabeled metabolites in rat plasma and kidneys were analysed by column-switch HPLC. Both tracers were evaluated with small animal PET imaging. Due to better pharmacokinetics, [(11)C]methyl-EXP3174 was further investigated via PET by co-injection with AT1R antagonist candesartan or the AT2R antagonist PD123,319. Binding selectivity to renal AT1 over AT2 and Mas receptors was demonstrated for [(11)C]methyl-losartan. Plasma metabolite analysis at 10 min revealed stability of [(11)C]methyl-losartan and [(11)C]methyl-EXP3174 with the presence of unchanged tracer at 70.8 ± 9.9% and 81.4 ± 6.0%, of total radioactivity, respectively. Contrary to [(11)C]methyl-losartan, co-injection of candesartan with [(11)C]methyl-EXP3174 reduced the proportion of unchanged tracer (but not metabolites), indicating that these metabolites do not bind to AT1R in rat kidneys. MicroPET images for both radiotracers displayed high kidney-to-background contrast. Candesartan significantly reduced [(11)C]methyl-EXP3174 uptake in the kidney, whereas no difference was observed following PD123,319 indicating binding selectivity for AT1R. [(11)C]Methyl-EXP3174 displayed a favorable binding profile compared to [(11)C]methyl-losartan for imaging renal AT1Rs supporting further studies to assess its full potential as a

  11. Effect of Triggering Receptor Expressed on Myeloid Cells 1 (TREM-1) Blockade in Rats with Cecal Ligation and Puncture (CLP)-Induced Sepsis. (United States)

    Shi, Xiaofeng; Zhang, Yue; Wang, Hao; Zeng, Sha


    BACKGROUND Blocking of TREM-1 signaling improves survival of mice with sepsis induced by Pseudomonas aeruginosa. However, whether TREM-1 blockade has beneficial effects in polymicrobial sepsis is poorly understood. Here, we aimed to investigate the effect of modulation of the TREM-1 pathway in rats with polymicrobial sepsis induced by cecal ligation and puncture (CLP). MATERIAL AND METHODS Normal Sprague-Dawley (SD) rats with sepsis induced by CLP were allocated randomly to received scramble peptide or LP17 via the jugular vein. Serum level of sTREM-1, IL6, TNF-α, and IL-1β were detected by ELISA assay. The mRNA and protein levels of JAK2 and STAT3 were detected by real-time PCR and Western blot analysis. RESULTS STREM-1 concentration was greatly and progressively increased in rats with CLP-induced sepsis, and the increase was attenuated by TREM-1 inhibitory peptide LP17. More than 60% survival was observed in rats at the experiment endpoint after LP17 treatment. TREM-1 blockade also attenuated the increased level of pro-inflammatory cytokines TNF-α, IL-6, and IL-1β, and thus attenuated systematic and distant inflammatory responses. Furthermore, TREM-1 blockade significantly attenuated the increased levels of pJAK2 and pSTAT3. CONCLUSIONS TREM-1 blockade by the use of an inhibitory peptide LP17 could prolong survival of rats with polymicrobial sepsis and attenuate systematic inflammatory responses through the JAK2/STAT3 signaling pathway. Our results suggest that modulation of TREM-1 by a synthetic peptide might be a potential therapeutic option for polymicrobial sepsis.

  12. Candesartan, an Angiotensin II AT1-Receptor Blocker and PPAR-γ Agonist, Reduces Lesion Volume and Improves Motor and Memory Function After Traumatic Brain Injury in Mice (United States)

    Villapol, Sonia; Yaszemski, Alexandra K; Logan, Trevor T; Sánchez-Lemus, Enrique; Saavedra, Juan M; Symes, Aviva J


    Traumatic brain injury (TBI) results in complex pathological reactions, the initial lesion worsened by secondary inflammation and edema. Angiotensin II (Ang II) is produced in the brain and Ang II receptor type 1 (AT1R) overstimulation produces vasoconstriction and inflammation. Ang II receptor blockers (ARBs) are neuroprotective in models of stroke but little is known of their effect when administered in TBI models. We therefore performed controlled cortical impact (CCI) injury on mice to investigate whether the ARB candesartan would mitigate any effects of TBI. We administered candesartan or vehicle to mice 5 h before CCI injury. Candesartan treatment reduced the lesion volume after CCI injury by approximately 50%, decreased the number of dying neurons, lessened the number of activated microglial cells, protected cerebral blood flow (CBF), and reduced the expression of the cytokine TGFβ1 while increasing expression of TGFβ3. Candesartan-treated mice also showed better motor skills on the rotarod 3 days after injury, and improved performance in the Morris water maze 4 weeks after injury. These results indicate that candesartan is neuroprotective, reducing neuronal injury, decreasing lesion volume and microglial activation, protecting CBF and improving functional behavior in a mouse model of TBI. Co-treatment with a peroxisome proliferator-activated receptor-gamma (PPARγ) antagonist significantly reduced some of the beneficial effects of candesartan after CCI, suggesting that PPARγ activation may contribute to part or to all of the neuroprotective effect of candesartan. Overall, our data suggest that ARBs with dual AT1R-blocking and PPARγ activation properties may have therapeutic value in treating TBI. PMID:22892395

  13. Towards an integrated approach on RAAS-blockade

    NARCIS (Netherlands)

    Lely, Anna Titia


    The role of the RAAS in cardiovascular and renal disease is much more complicated than initially assumed. Whereas blockade of the system by ACEi or AT-1 blockade has turned out to be one of the most effective therapies in prevention and treatment of cardiovascular and renal disease, still in many

  14. Angiotensin II modulates mouse skeletal muscle resting conductance to chloride and potassium ions and calcium homeostasis via the AT1 receptor and NADPH oxidase. (United States)

    Cozzoli, Anna; Liantonio, Antonella; Conte, Elena; Cannone, Maria; Massari, Ada Maria; Giustino, Arcangela; Scaramuzzi, Antonia; Pierno, Sabata; Mantuano, Paola; Capogrosso, Roberta Francesca; Camerino, Giulia Maria; De Luca, Annamaria


    Angiotensin II (ANG II) plays a role in muscle wasting and remodeling; however, little evidence shows its direct effects on specific muscle functions. We presently investigated the acute in vitro effects of ANG II on resting ionic conductance and calcium homeostasis of mouse extensor digitorum longus (EDL) muscle fibers, based on previous findings that in vivo inhibition of ANG II counteracts the impairment of macroscopic ClC-1 chloride channel conductance (gCl) in the mdx mouse model of muscular dystrophy. By means of intracellular microelectrode recordings we found that ANG II reduced gCl in the nanomolar range and in a concentration-dependent manner (EC50 = 0.06 μM) meanwhile increasing potassium conductance (gK). Both effects were inhibited by the ANG II receptors type 1 (AT1)-receptor antagonist losartan and the protein kinase C inhibitor chelerythrine; no antagonism was observed with the AT2 antagonist PD123,319. The scavenger of reactive oxygen species (ROS) N-acetyl cysteine and the NADPH-oxidase (NOX) inhibitor apocynin also antagonized ANG II effects on resting ionic conductances; the ANG II-dependent gK increase was blocked by iberiotoxin, an inhibitor of calcium-activated potassium channels. ANG II also lowered the threshold for myofiber and muscle contraction. Both ANG II and the AT1 agonist L162,313 increased the intracellular calcium transients, measured by fura-2, with a two-step pattern. These latter effects were not observed in the presence of losartan and of the phospholipase C inhibitor U73122 and the in absence of extracellular calcium, disclosing a Gq-mediated calcium entry mechanism. The data show for the first time that the AT1-mediated ANG II pathway, also involving NOX and ROS, directly modulates ion channels and calcium homeostasis in adult myofibers. Copyright © 2014 the American Physiological Society.

  15. Acute effects of angiotensin-converting enzyme inhibition versus angiotensin II receptor blockade on cardiac sympathetic activity in patients with heart failure. (United States)

    Azevedo, Eduardo R; Mak, Susanna; Floras, John S; Parker, John D


    The beneficial effects of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II (ANG II) receptor antagonists in patients with heart failure secondary to reduced ejection fraction (HFrEF) are felt to result from prevention of the adverse effects of ANG II on systemic afterload and renal homeostasis. However, ANG II can activate the sympathetic nervous system, and part of the beneficial effects of ACE inhibitors and ANG II antagonists may result from their ability to inhibit such activation. We examined the acute effects of the ACE inhibitor captopril (25 mg, n = 9) and the ANG II receptor antagonist losartan (50 mg, n = 10) on hemodynamics as well as total body and cardiac norepinephrine spillover in patients with chronic HFrEF. Hemodynamic and neurochemical measurements were made at baseline and at 1, 2, and 4 h after oral dosing. Administration of both drugs caused significant reductions in systemic arterial, cardiac filling, and pulmonary artery pressures ( P < 0.05 vs. baseline). There was no significant difference in the magnitude of those hemodynamic effects. Plasma concentrations of ANG II were significantly decreased by captopril and increased by losartan ( P < 0.05 vs. baseline for both). Total body sympathetic activity increased in response to both captopril and losartan ( P < 0.05 vs. baseline for both); however, there was no change in cardiac sympathetic activity in response to either drug. The results of the present study do not support the hypothesis that the acute inhibition of the renin-angiotensin system has sympathoinhibitory effects in patients with chronic HFrEF. Copyright © 2017 the American Physiological Society.

  16. Angiotensin II Reduces Cardiac AdipoR1 Expression through AT1 Receptor/ROS/ERK1/2/c-Myc Pathway (United States)

    Lei, Hong; Wang, Cheng; Wu, Li-Peng; Wang, Jin-Yu; Fu, Feng-Ying; Zhu, Wei-Guo; Wu, Li-Ling


    Adiponectin, an abundant adipose tissue-derived protein, exerts protective effect against cardiovascular disease. Adiponectin receptors (AdipoR1 and AdipoR2) mediate the beneficial effects of adiponectin on the cardiovascular system. However, the alteration of AdipoRs in cardiac remodeling is not fully elucidated. Here, we investigated the effect of angiotensin II (AngII) on cardiac AdipoRs expression and explored the possible molecular mechanism. AngII infusion into rats induced cardiac hypertrophy, reduced AdipoR1 but not AdipoR2 expression, and attenuated the phosphorylations of adenosine monophosphate-activated protein kinase and acetyl coenzyme A carboxylase, and those effects were all reversed by losartan, an AngII type 1 (AT1) receptor blocker. AngII reduced expression of AdipoR1 mRNA and protein in cultured neonatal rat cardiomyocytes, which was abolished by losartan, but not by PD123319, an AT2 receptor antagonist. The antioxidants including reactive oxygen species (ROS) scavenger NAC, NADPH oxidase inhibitor apocynin, Nox2 inhibitor peptide gp91 ds-tat, and mitochondrial electron transport chain complex I inhibitor rotenone attenuated AngII-induced production of ROS and phosphorylation of extracellular signal-regulated kinase (ERK) 1/2. AngII-reduced AdipoR1 expression was reversed by pretreatment with NAC, apocynin, gp91 ds-tat, rotenone, and an ERK1/2 inhibitor PD98059. Chromatin immunoprecipitation assay demonstrated that AngII provoked the recruitment of c-Myc onto the promoter region of AdipoR1, which was attenuated by PD98059. Moreover, AngII-induced DNA binding activity of c-Myc was inhibited by losartan, NAC, apocynin, gp91 ds-tat, rotenone, and PD98059. c-Myc small interfering RNA abolished the inhibitory effect of AngII on AdipoR1 expression. Our results suggest that AngII inhibits cardiac AdipoR1 expression in vivo and in vitro and AT1 receptor/ROS/ERK1/2/c-Myc pathway is required for the downregulation of AdipoR1 induced by AngII. PMID

  17. Angiotensin II reduces cardiac AdipoR1 expression through AT1 receptor/ROS/ERK1/2/c-Myc pathway.

    Directory of Open Access Journals (Sweden)

    Li Li

    Full Text Available Adiponectin, an abundant adipose tissue-derived protein, exerts protective effect against cardiovascular disease. Adiponectin receptors (AdipoR1 and AdipoR2 mediate the beneficial effects of adiponectin on the cardiovascular system. However, the alteration of AdipoRs in cardiac remodeling is not fully elucidated. Here, we investigated the effect of angiotensin II (AngII on cardiac AdipoRs expression and explored the possible molecular mechanism. AngII infusion into rats induced cardiac hypertrophy, reduced AdipoR1 but not AdipoR2 expression, and attenuated the phosphorylations of adenosine monophosphate-activated protein kinase and acetyl coenzyme A carboxylase, and those effects were all reversed by losartan, an AngII type 1 (AT1 receptor blocker. AngII reduced expression of AdipoR1 mRNA and protein in cultured neonatal rat cardiomyocytes, which was abolished by losartan, but not by PD123319, an AT2 receptor antagonist. The antioxidants including reactive oxygen species (ROS scavenger NAC, NADPH oxidase inhibitor apocynin, Nox2 inhibitor peptide gp91 ds-tat, and mitochondrial electron transport chain complex I inhibitor rotenone attenuated AngII-induced production of ROS and phosphorylation of extracellular signal-regulated kinase (ERK 1/2. AngII-reduced AdipoR1 expression was reversed by pretreatment with NAC, apocynin, gp91 ds-tat, rotenone, and an ERK1/2 inhibitor PD98059. Chromatin immunoprecipitation assay demonstrated that AngII provoked the recruitment of c-Myc onto the promoter region of AdipoR1, which was attenuated by PD98059. Moreover, AngII-induced DNA binding activity of c-Myc was inhibited by losartan, NAC, apocynin, gp91 ds-tat, rotenone, and PD98059. c-Myc small interfering RNA abolished the inhibitory effect of AngII on AdipoR1 expression. Our results suggest that AngII inhibits cardiac AdipoR1 expression in vivo and in vitro and AT1 receptor/ROS/ERK1/2/c-Myc pathway is required for the downregulation of AdipoR1 induced by AngII.

  18. An efficient synthesis of a rationally designed 1,5 disubstituted imidazole AT1 Angiotensin II receptor antagonist: reorientation of imidazole pharmacophore groups in losartan reserves high receptor affinity and confirms docking studies (United States)

    Agelis, George; Roumelioti, Panagiota; Resvani, Amalia; Durdagi, Serdar; Androutsou, Maria-Eleni; Kelaidonis, Konstantinos; Vlahakos, Demetrios; Mavromoustakos, Thomas; Matsoukas, John


    A new 1,5 disubstituted imidazole AT1 Angiotensin II (AII) receptor antagonist related to losartan with reversion of butyl and hydroxymethyl groups at the 2-, 5-positions of the imidazole ring was synthesized and evaluated for its antagonist activity ( V8). In vitro results indicated that the reorientation of butyl and hydroxymethyl groups on the imidazole template of losartan retained high binding affinity to the AT1 receptor concluding that the spacing of the substituents at the 2,5- positions is of primary importance. The docking studies are confirmed by binding assay results which clearly show a comparable binding score of the designed compound V8 with that of the prototype losartan. An efficient, regioselective and cost effective synthesis renders the new compound as an attractive candidate for advanced toxicological evaluation and a drug against hypertension.

  19. The intrathecal administration of losartan, an AT1 receptor antagonist, produces an antinociceptive effect through the inhibiton of p38 MAPK phosphorylation in the mouse formalin test. (United States)

    Nemoto, Wataru; Ogata, Yoshiki; Nakagawasai, Osamu; Yaoita, Fukie; Tanado, Takeshi; Tan-No, Koichi


    We have recently reported that an intrathecal (i.t.) administration of angiotensin II (Ang II) into mice induces a nociceptive behavior accompanied by the activation of p38 MAPK signaling via AT1 receptors (Nemoto et al., 2013, Mol. Pain 9, 38). These results suggested that Ang II participates in the facilitation of nociceptive transmission in the spinal cord. In the present study, we used formalin test to examine the effect of i.t.-administered losartan, an AT1 receptor antagonist, and determine whether Ang II acts as a neurotransmitter and/or neuromodulator in the spinal transmission of nociceptive information. When administered i.t. 5 min before the injection of a 2% formalin solution into the plantar surface of the hindpaw, losartan (30-100 nmol) produced a dose-dependent and significant antinociceptive effect during both the first and second phases of the test. In the superficial dorsal horn of the spinal cord (laminae I and II), the fluorescence intensities for Ang II and phospho-p38 MAPK were both significantly increased on the ipsilateral side 3 min after the injection of formalin compared to saline-treated controls. Moreover, the increase of phospho-p38 MAPK fluorescence intensity was significantly inhibited by the i.t. administration of losartan (54.8 nmol) 5 min prior to formalin. These results indicate that losartan produces an antinociceptive effect through the inhibition of p38 MAPK phosphorylation in the mouse formalin test and that Ang II may act as a neurotransmitter and/or neuromodulator in the spinal transmission of nociceptive information. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  20. AT2 Receptors Targeting Cardiac Protection Post-Myocardial Infarction

    DEFF Research Database (Denmark)

    Kaschina, Elena; Lauer, Dilyara; Schmerler, Patrick


    is preserved over periods of up to four months. Depending on the experimental protocol, the AT2R also attenuates post-MI left ventricular remodeling or protects the heart from early left ventricular thinning and rupture. In combination with AT1-receptor blockade or deficiency, post-MI cardiac hypertrophy...... deficiency or overexpression, treatment with an AT1-receptor blocker leading to indirect stimulation of the unopposed AT2-receptor, or studies using AT2-receptor agonists. It is a common finding in these studies that the AT2-receptor improves cardiac function in the early phase post-MI, and that this effect...

  1. Tandospirone, a 5-HT1A partial agonist, ameliorates aberrant lactate production in the prefrontal cortex of rats exposed to blockade of N-methy-D-aspartate receptors; Towards the therapeutics of cognitive impairment of schizophrenia

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    Takashi eUehara


    Full Text Available Rationale Augmentation therapy with serotonin-1A (5-HT1A receptor partial agonists has been suggested to improve cognitive deficits in patients with schizophrenia. Decreased activity of prefrontal cortex may provide a basis for cognitive deficits of the disease. Lactate plays a significant role in the supply of energy to the brain, and glutamatergic neurotransmission contributes to lactate production.Objectives and methods The purposes of this study were to examine the effect of repeated administration (once a daily for 4 days of tandospirone (0.05 and 5 mg/kg on brain energy metabolism, as represented by extracellular lactate concentration (eLAC in the medial prefrontal cortex (mPFC of young adult rats..Results Four-day treatment with MK-801, an NMDA-R antagonist, prolonged eLAC elevation induced by foot shock stress (FS. Co-administration with the high-dose tandospirone suppressed prolonged FS-induced eLAC elevation in rats receiving MK-801, whereas tandospirone by itself did not affected eLAC increment.Conclusions These results suggest that stimulation of 5-HT1A receptors ameliorates abnormalities of energy metabolism in the mPFC due to blockade of NMDA receptors. These findings provide a possible mechanism based on brain energy metabolism by which 5-HT1A agonism improve cognitive impairment in schizophrenia and related disorders.

  2. Evaluation of the Counter-regulatory Responses to Hypoglycemia in Patients with Type 1 Diabetes during Opiate Receptor Blockade with Naltrexone

    DEFF Research Database (Denmark)

    Naik, Sarita; Belfort-DeAguiar, Renata; Sejling, Anne-Sophie


    AIMS: Hypoglycemia is the major limiting factor in achieving optimal glycemic control in people with type 1 diabetes (T1DM), especially intensively treated patients with impaired glucose counterregulation during hypoglycemia. Naloxone, an opiate receptor blocker, has been reported to enhance...... responses were observed. CONCLUSION: In contrast to the intravenous opiate receptor blocker naloxone, overnight administration of the oral long acting opiate receptor blocker, naltrexone, at a clinically used dose, had a limited effect on the counterregulatory response to hypoglycemia in intensively treated...

  3. Angiotensin 1-7 receptor and angiotensin ii receptor 2 blockades prevent the increased serum and kidney nitric oxide levels in response to angiotensin ii administration: Gender-related difference

    Directory of Open Access Journals (Sweden)

    Tahereh Safari


    Conclusions: The renal vasculature of male rats may provide more response to Ang II administration-induced NO, which is dependent on masR and AT2R. During dual masR + AT2R blockades, the kidney NO formation wasreduced in a non-gender related manner.

  4. Typical and Atypical Antipsychotic Drugs Increase Extracellular Histamine Levels in the Rat Medial Prefrontal Cortex: Contribution of Histamine H1 Receptor Blockade

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    Kjell A Svensson


    Full Text Available Atypical antipsychotics such as clozapine and olanzapine have been shown to enhance histamine turnover and this effect has been hypothesized to contribute to their improved therapeutic profile compared to typical antipsychotics. In the present study, we examined the effects of antipsychotic drugs on histamine (HA efflux in the mPFC of the rat by means of in vivo microdialysis and sought to differentiate the receptor mechanisms which underlie such effects. Olanzapine and clozapine increased mPFC HA efflux in a dose related manner. Increased HA efflux was also observed after quetiapine, chlorpromazine and perphenazine treatment. We found no effect of the selective 5-HT2A antagonist MDL100907, 5-HT2c antagonist SB242084 or the 5-HT6 antagonist Ro 04-6790 on mPFC HA efflux. HA efflux was increased following treatment with selective H1 receptor antagonists pyrilamine, diphenhydramine and triprolidine, the H3 receptor antagonist ciproxifan and the mixed 5HT2A/H1 receptor antagonist ketanserin. The potential novel antipsychotic drug FMPD, which has a lower affinity at H1 receptors than olanzapine, did not affect HA efflux. Similarly, other antipsychotics with lower H1 receptor affinity (risperidone, aripiprazole and haloperidol were also without effect on HA efflux. Perfusion of clozapine and pyrilamine into the TMN, but not the mPFC, increased local HA efflux. Finally, HA efflux after antipsychotic treatment was significantly correlated with affinity at H1 receptors whereas 9 other receptors, including 5-HT2A, were not. These results demonstrate that both typical and atypical antipsychotics increase mPFC histamine efflux and this effect may be mediated via antagonism of histamine H1 receptors.

  5. Systemic blockade of dopamine D2-like receptors increases high-voltage spindles in the globus pallidus and motor cortex of freely moving rats.

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    Chen Yang

    Full Text Available High-voltage spindles (HVSs have been reported to appear spontaneously and widely in the cortical-basal ganglia networks of rats. Our previous study showed that dopamine depletion can significantly increase the power and coherence of HVSs in the globus pallidus (GP and motor cortex of freely moving rats. However, it is unclear whether dopamine regulates HVS activity by acting on dopamine D₁-like receptors or D₂-like receptors. We employed local-field potential and electrocorticogram methods to simultaneously record the oscillatory activities in the GP and primary motor cortex (M1 in freely moving rats following systemic administration of dopamine receptor antagonists or saline. The results showed that the dopamine D₂-like receptor antagonists, raclopride and haloperidol, significantly increased the number and duration of HVSs, and the relative power associated with HVS activity in the GP and M1 cortex. Coherence values for HVS activity between the GP and M1 cortex area were also significantly increased by dopamine D₂-like receptor antagonists. On the contrary, the selective dopamine D₁-like receptor antagonist, SCH23390, had no significant effect on the number, duration, or relative power of HVSs, or HVS-related coherence between M1 and GP. In conclusion, dopamine D₂-like receptors, but not D₁-like receptors, were involved in HVS regulation. This supports the important role of dopamine D₂-like receptors in the regulation of HVSs. An siRNA knock-down experiment on the striatum confirmed our conclusion.

  6. TRC120038, a Novel Dual AT1/ETA Receptor Blocker for Control of Hypertension, Diabetic Nephropathy, and Cardiomyopathy in ob-ZSF1 Rats

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    Anookh Mohanan


    Full Text Available In hypertensive subjects, angiotensin II and endothelin participate in a manner involving closely interwoven pathways in increasing blood pressure (BP and inducing end organ damage. The primary objective of this study was to determine the effect of TRC120038, a novel dual AT1/ETA receptor blocker on BP, in obese Zucker spontaneously hypertensive fatty rats (ob-ZSF1, an animal model of moderate hypertension, diabetes with progressive renal and cardiac dysfunction. Ob-ZSF1 rats loaded with 0.5% salt were treated with TRC120038 (11.8 mg/kg bid. or candesartan cilexetil (0.3 mg/kg od. or vehicle control. Blood pressure (by radio-telemetry and renal functional markers were monitored throughout the study. Cardiac function was assessed terminally by pressure volume catheter. Markers for renal dysfunction were measured and changes were evaluated histopathologically. TRC120038 showed greater fall in both systolic and diastolic BP in comparison to candesartan at its maximum antihypertensive dose. TRC120038 also reduced the severity of renal dysfunction and preserved cardiac function in ob-ZSF1 rat.

  7. Reciprocal Roles of Angiotensin II and Angiotensin II Receptors Blockade (ARB in Regulating Cbfa1/RANKL via cAMP Signaling Pathway: Possible Mechanism for Hypertension-Related Osteoporosis and Antagonistic Effect of ARB on Hypertension-Related Osteoporosis

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    Ji-Yao Li


    Full Text Available Hypertension is a risk factor for osteoporosis. Animal and epidemiological studies demonstrate that high blood pressure is associated with increased calcium loss, elevated parathyroid hormone, and increased calcium movement from bone. However, the mechanism responsible for hypertension-related osteoporosis remains elusive. Recent epidemiological studies indicate the benefits of Angiotensin II Receptors Blockade (ARB on decreasing fracture risks. Since receptors for angiotensin II, the targets of ARB, are expressed in both osteoblasts and osteoclasts, we postulated that angiotensin II plays an important role in hypertension-related osteoporosis. Cbfa1 and RANKL, the important factors for maintaining bone homeostasis and key mediators in controlling osteoblast and osteoclast differentiation, are both regulated by cAMP-dependent signaling. Angiotensin II along with factors such as LDL, HDL, NO and homocysteine that are commonly altered both in hypertension and osteoporosis, can down-regulate the expression of Cbfa1 but up-regulate RANKL expression via the cAMP signaling pathway. We thus hypothesized that, by altering the ratio of Cbfa1/RANKL expression via the cAMP-dependent pathway, angiotensin II differently regulates osteoblast and osteoclast differentiation leading to enhanced bone resorption and reduced bone formation. Since ARB can antagonize the adverse effect of angiotensin II on bone by lowering cAMP levels and modifying other downstream targets, including LDL, HDL, NO and Cbfa1/RANKL, we propose the hypothesis that the antagonistic effects of ARB may also be exerted via cAMP signaling pathway.

  8. Bradykinin antagonist counteracts the acute effect of both angiotensin-converting enzyme inhibition and of angiotensin receptor blockade on the lower limit of autoregulation of cerebral blood flow

    DEFF Research Database (Denmark)

    Sigurdsson, Sigurdur T; Paulson, Olaf B; Høj Nielsen, Arne


    The lower limit of autoregulation of cerebral blood flow (CBF) can be modulated with both angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARB). The influence of bradykinin antagonism on ARB-induced changes was the subject of this study. CBF was measured in Sprague......-Dawley rats with laser Doppler technique. The blood pressure was lowered by controlled bleeding. Six groups of rats were studied: a control group and five groups given drugs intravenously: an ACE inhibitor (enalaprilat), an ARB (candesartan), a bradykinin-2 receptor antagonist (Hoe 140), a combination...

  9. Angiotensin II receptor blockade does not protect against progressive loss of residual renal function in hemodialysis patients: A randomized controlled trial (SAFIR study)

    DEFF Research Database (Denmark)

    Kjærgaard, Krista Dybtved; Peters, Christian Daugaard; Jespersen, Bente

    centers and randomized to placebo or the angiotensin II receptor blocker irbesartan 300 mg daily. Target systolic blood pressure (BP) was 140 mmHg. Outcomes were GFR measured as the mean of creatinine and urea renal clearance, urine volume and time to anuria. Results: Of the 82 patients randomized...

  10. initial angiotensin receptor blockade-induced decrease in albuminuria is associated with long-term renal outcome in type 2 diabetic patients with microalbuminuria

    DEFF Research Database (Denmark)

    Hellemons, Merel E; Persson, Frederik; Bakker, Stephan J L


    We aimed to investigate the individual impact of initial responses in urinary albumin excretion (UAE) and systolic blood pressure (SBP) to angiotensin II receptor blocker (ARB) treatment on long-term renal outcome in patients with type 2 diabetes and microalbuminuria....

  11. Blockade of sensory abnormalities and kinin B(1) receptor expression by N-acetyl-L-cysteine and ramipril in a rat model of insulin resistance. (United States)

    Ismael, Mahmoud Ali; Talbot, Sébastien; Carbonneau, Cynthia L; Beauséjour, Christian M; Couture, Réjean


    Glucose-fed rat is a model of insulin resistance that displays sensory polyneuropathy and hypertension. This study aimed at comparing the beneficial effects of N-acetyl-L-cysteine (NAC, antioxidant) and ramipril (angiotensin-1 converting enzyme inhibitor) on tactile and cold allodynia induced by chronic glucose feeding. Impact of these treatments was also assessed on hypertension, plasma glucose and insulin concentrations, insulin resistance and kinin B(1) receptor expression. Male Wistar rats (50-75 g) were given 10% d-glucose in their drinking water for 11 weeks or tap water (controls). Glucose-fed rats were treated either with NAC (1 g/kg/day, gavage), ramipril (1 mg/kg/day in drinking water) or no drug during the last 5 weeks. Glucose feeding for 6 weeks induced a significant increase in systolic blood pressure and hyperglycaemia which was accompanied by tactile and cold allodynia. At 11 weeks, plasma insulin, insulin resistance (HOMA index), kinin B(1) receptor mRNA in spinal cord and renal cortex and B(1) receptor binding sites in spinal cord were enhanced in glucose-fed rats. NAC and ramipril caused a progressive to complete inhibition of tactile and cold allodynia from 6 to 11 weeks. High systolic blood pressure, hyperinsulinemia, insulin resistance and kinin B(1) receptor expression were also normalized or attenuated in glucose-fed rats by either treatment. Results suggest that chronic treatment with an antioxidant or an ACE inhibitor provides similar beneficial effects on sensory polyneuropathy, hypertension and insulin resistance in glucose-fed rats. Both therapies were associated with a reduction of the expression of the pro-nociceptive kinin B(1) receptor.

  12. Blockade of growth hormone secretagogue receptor 1A signaling by JMV 2959 attenuates the NMDAR antagonist, phencyclidine-induced impairments in prepulse inhibition. (United States)

    Engel, Jörgen A; Jerlhag, Elisabet; Svensson, Lennart; Smith, Roy G; Egecioglu, Emil


    Schizophrenic-spectrum patients commonly display deficits in preattentive information processing as evidenced, for example, by disrupted prepulse inhibition (PPI), a measure of sensorimotor gating. Similar disruptions in PPI can be induced in rodents and primates by the psychotomimetic drug phencyclidine (PCP), a noncompetitive inhibitor of the NMDA receptor. Mounting evidence suggests that the hunger hormone ghrelin and its constitutively active receptor influences neuronal circuits involved in the regulation of mood and cognition. In the present series of experiments, we investigated the effects of ghrelin and the growth hormone secretagogue receptor (GHS-R1A) neutral antagonist, JMV 2959, on acoustic startle responses (ASR), PPI, and PCP-induced alterations in PPI. Intraperitoneal (i.p.) administration of ghrelin (0.033, 0.1, and 0.33 mg/kg) did not alter the ASR or PPI in rats. Conversely, i.p. injection of JMV 2959 (1, 3, and 6 mg/kg), dose dependently decreased the ASR and increased PPI. Pretreatment with JMV 2959 at a dose with no effect on ASR or PPI per se, completely blocked PCP-induced (2 mg/kg) deficits in PPI while pretreatment with the highest dose of ghrelin did not potentiate or alter PPI responses of a sub-threshold dose of PCP (0.75 mg/kg). These findings indicate that the GHS-R1A is involved in specific behavioral effects of PCP and may have relevance for patients with schizophrenia.

  13. Blockade of insulin-like growth factor type-1 receptor with cixutumumab (IMC-A12): a novel approach to treatment for multiple cancers. (United States)

    Rowinsky, Eric K; Schwartz, Jonathan D; Zojwalla, Naseem; Youssoufian, Hagop; Fox, Floyd; Pultar, Philippe; Novosyadlyy, Ruslan; Cosaert, Jan; Ludwig, Dale L


    Insulin-like growth factor type-1 receptor (IGF-1R) plays a central role in cell proliferation and survival and is overexpressed in many tumor types. Notably, IGF-1R-mediated signaling confers resistance to diverse cytotoxic, hormonal, and biologic agents, suggesting that therapies targeting IGF-1R may be effective against a broad range of human malignancies. Cixutumumab (IMC-A12; ImClone Systems) is a fully human immunoglobulin G1 (IgG1) monoclonal antibody that specifically inhibits IGF-1R signaling. Binding of cixutumumab to IGF-1R results in receptor internalization and degradation. Because cixutumumab is an IgG1 monoclonal antibody, it may induce additional cytotoxicity via immune effector mechanisms such as antibody-dependent cellular cytotoxicity. In preclinical studies, cixutumumab monotherapy resulted in growth inhibition of multiple experimental cancers. Moreover, cixutumumab safely enhanced the tumor growth inhibitory and cytotoxic effects of a broad range of chemotherapeutics, and modulated the action of agents that target hormone receptors and signal transduction, which may have implications for cancer therapy. Herein, we review published preclinical and clinical data for cixutumumab and provide a comprehensive overview of selected clinical studies.

  14. Structure of the Human Angiotensin II Type 1 (AT1) Receptor Bound to Angiotensin II from Multiple Chemoselective Photoprobe Contacts Reveals a Unique Peptide Binding Mode* (United States)

    Fillion, Dany; Cabana, Jérôme; Guillemette, Gaétan; Leduc, Richard; Lavigne, Pierre; Escher, Emanuel


    Breakthroughs in G protein-coupled receptor structure determination based on crystallography have been mainly obtained from receptors occupied in their transmembrane domain core by low molecular weight ligands, and we have only recently begun to elucidate how the extracellular surface of G protein-coupled receptors (GPCRs) allows for the binding of larger peptide molecules. In the present study, we used a unique chemoselective photoaffinity labeling strategy, the methionine proximity assay, to directly identify at physiological conditions a total of 38 discrete ligand/receptor contact residues that form the extracellular peptide-binding site of an activated GPCR, the angiotensin II type 1 receptor. This experimental data set was used in homology modeling to guide the positioning of the angiotensin II (AngII) peptide within several GPCR crystal structure templates. We found that the CXC chemokine receptor type 4 accommodated the results better than the other templates evaluated; ligand/receptor contact residues were spatially grouped into defined interaction clusters with AngII. In the resulting receptor structure, a β-hairpin fold in extracellular loop 2 in conjunction with two extracellular disulfide bridges appeared to open and shape the entrance of the ligand-binding site. The bound AngII adopted a somewhat vertical binding mode, allowing concomitant contacts across the extracellular surface and deep within the transmembrane domain core of the receptor. We propose that such a dualistic nature of GPCR interaction could be well suited for diffusible linear peptide ligands and a common feature of other peptidergic class A GPCRs. PMID:23386604

  15. Blockade of NMDA receptor subtype NR2B prevents seizures but not apoptosis of dentate gyrus neurons in bacterial meningitis in infant rats

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    Täuber Martin G


    Full Text Available Abstract Background Excitotoxic neuronal injury by action of the glutamate receptors of the N-methyl-d-aspartate (NMDA subtype have been implicated in the pathogenesis of brain damage as a consequence of bacterial meningitis. The most potent and selective blocker of NMDA receptors containing the NR2B subunit is (R,S-alpha-(4-hydroxyphenyl-beta-methyl-4-(phenylmethyl-1-piperid inepropanol (RO 25-6981. Here we evaluated the effect of RO 25-6981 on hippocampal neuronal apoptosis in an infant rat model of meningitis due to Streptococcus pneumoniae. Animals were randomized for treatment with RO 25-6981 at a dosage of either 0.375 mg (15 mg/kg; n = 28 or 3.75 mg (150 mg/kg; n = 15 every 3 h or an equal volume of sterile saline (250 μl; n = 40 starting at 12 h after infection. Eighteen hours after infection, animals were assessed clinically and seizures were observed for a period of 2 h. At 24 h after infection animals were sacrificed and brains were examined for apoptotic injury to the dentate granule cell layer of the hippocampus. Results Treatment with RO 25-6981 had no effect on clinical scores, but the incidence of seizures was reduced (P Conclusions Treatment with a highly selective blocker of NMDA receptors containing the NR2B subunit failed to protect hippocampal neurons from injury in this model of pneumococcal meningitis, while it had some beneficial effect on the incidence of seizures.


    Directory of Open Access Journals (Sweden)

    Izabella Silva De Jesus Pinto


    Full Text Available IIntrathecal injection of bombesin (BBS promoted hypertensive and sympathoexcitatory effects in normotensive (NT rats. However, the involvement of rostral ventrolateral medulla (RVLM in these responses is still unclear. In the present study, we investigated: (1 the effects of BBS injected bilaterally into RVLM on cardiorespiratory and sympathetic activity in NT and spontaneously hypertensive rats (SHR; (2 the contribution of RVLM bombesin type 1 receptors (BB1 to the maintenance of hypertension in SHR. Urethane-anesthetized rats (1.2 g · kg−1, i.v. were instrumented to record mean arterial pressure (MAP, diaphragm (DIA motor and renal sympathetic nerve activity (RSNA. In NT rats and SHR, BBS (0.3 mM nanoinjected into RVLM increased MAP (33.9 ± 6.6 mmHg and 37.1 ± 4.5 mmHg, respectively; p < 0.05 and RSNA (97.8 ± 12.9 % and 84.5 ± 18.1 %, respectively; p < 0.05. In SHR, BBS also increased DIA burst amplitude (115.3 ± 22.7 %; p < 0.05. BB1 receptors antagonist (BIM-23127; 3 mM reduced MAP (-19.9 ± 4.4 mmHg; p < 0.05 and RSNA (-17.7 ± 3.8 %; p < 0.05 in SHR, but not in NT rats (-2.5 ± 2.8 mmHg; -2.7 ± 5.6 %, respectively. These results show that BBS can evoke sympathoexcitatory and pressor responses by activating RVLM BB1 receptors. This pathway might be involved in the maintenance of high levels of arterial blood pressure in SHR.

  17. Treatment of transplanted CT26 tumour with dendritic cell vaccine in combination with blockade of vascular endothelial growth factor receptor 2 and CTLA-4

    DEFF Research Database (Denmark)

    Pedersen, Anders Elm; Buus, S; Claesson, M H


    We investigated the anti CT26 tumour effect of dendritic cell based vaccination with the MuLV gp70 envelope protein-derived peptides AH1 and p320-333. Vaccination lead to generation of AH1 specific cytotoxic lymphocytes (CTL) and some decrease in tumour growth of simultaneously inoculated CT26...... cells. After combination with an antibody against VEGF receptor 2 (DC101), a significant increase in survival of the tumour cell recipients was observed. Also, monotherapy with an antibody against CTLA-4 (9H10), led to approximately 100% survival of tumour cell recipients. However, effective treatment...

  18. Angiotensin receptor blockade in acute stroke. The Scandinavian Candesartan Acute Stroke Trial: rationale, methods and design of a multicentre, randomised- and placebo-controlled clinical trial (NCT00120003)

    DEFF Research Database (Denmark)

    Sandset, Else Charlotte; Murray, Gordon; Boysen, Gudrun Margrethe


    Elevated blood pressure following acute stroke is common, and yet early antihypertensive treatment is controversial. ACCESS suggested a beneficial effect of the angiotensin receptor blocker candesartan in the acute phase of stroke, but these findings need to be confirmed in new, large trials. AIMS......, Sweden, Denmark, Belgium, Germany, Poland, Lithuania, Estonia and Finland. STUDY OUTCOMES: There are two co-primary effect variables: • Functional status at 6-months, measured by the modified Rankin Scale, and • vascular death, myocardial infarction or stroke during the first 6-months. Secondary outcome...

  19. Of fads, fashion, surrogate endpoints and dual RAS blockade. (United States)

    Messerli, Franz H; Staessen, Jan A; Zannad, Faiez


    Dual renin-angiotensin system (RAS) blockade, mostly by combining an angiotensin converting enzyme (ACE) inhibitor with an angiotensin receptor blocker (ARB), is increasingly used in patients with hypertension and diabetes and/or proteinuria and in those with resistant heart failure. However, in the zest of achieving greater nephroprotection and cardioprotection, even patients with uncomplicated essential hypertension are not uncommonly treated with dual RAS blockade. In 2003 the COOPERATE trial, seemed to confirm that dual RAS blockade was beneficial and that proteinuria reduction was synonymous with nephroprotection. This study had to be withdrawn recently attesting to the suspicion that the data looked to good to be true. Moreover, the large prospective ONTARGET data argue against a nephroprotective effect of dual RAS blockade and together with renal findings from ACCOMPLISH, cast doubt on albuminuria/proteinuria being a reliable surrogate endpoint for renal outcome. Although in heart failure, dual RAS blockade had some benefit without reducing mortality, there remains a distinct safety issue with regard to hyperkalemia and elevated creatinine. Neither in ischaemic heart disease nor in left ventricular hypertrophy had dual RAS blockade any benefits when compared with single RAS blockade. Of note, the combination of an ACE inhibitor with an ARB was recently shown to reduce the risk of dementia. All dual RAS blockade may be created equal and the combination of valsartan with aliskiren, a direct renin inhibitor will be evaluated in diabetic patients in the prospective, randomized ALTITUDE study. For the time being, given the adverse effects and lack of consistent survival benefits, the use of dual RAS blockade should be avoided unless ironclad data emerge to the contrary.

  20. Angiotensin II Type 1 receptor (AT1) signaling in astrocytes regulates synaptic degeneration-induced leukocyte entry to the central nervous system

    DEFF Research Database (Denmark)

    Füchtbauer, L; Groth-Rasmussen, Maria; Holm, Thomas Hellesøe


    in the dentate gyrus following axonal transection was totally abrogated in GFAP-IκBα-dn mice. Whereas angiotensin II was upregulated in microglia and astrocytes in the dentate gyrus post-lesion, AT1 was exclusively expressed on astrocytes. Blocking AT1 with Candesartan led to significant increase in numbers...

  1. Effects of angiotensin II receptor blockade on cerebral, cardiovascular, counter-regulatory, and symptomatic responses during hypoglycaemia in patients with type 1 diabetes

    DEFF Research Database (Denmark)

    Færch, Louise H; Thorsteinsson, Birger; Tarnow, Lise


    during hypoglycaemia. METHODS: Nine patients with type 1 diabetes and high spontaneous RAS activity were included in a double-blind, randomised, cross-over study on the effect of angiotensin II receptor antagonist (candesartan 32 mg) or placebo for one week on cognitive function, cardiovascular...... parameters, hormonal counter-regulatory response, substrate mobilisation, and symptoms during hypoglycaemia induced by two hyperinsulinaemic, hypoglycaemic clamps. RESULTS: Compared to placebo, candesartan did neither change performance of the cognitive tests nor the EEG at a plasma glucose concentration...... of 2.6±0.2 mmol/l. During candesartan treatment, the QT interval in the ECG was not affected. No effect of candesartan was observed in the hormonal counter-regulatory responses, in substrate concentrations, or in symptom scores. A 36% reduced glucose infusion rate during hypoglycaemia with candesartan...

  2. The second Lilly Prize Lecture, University of Newcastle, July 1977. beta-Adrenergic receptor blockade in hypertension, past, present and future. (United States)

    Prichard, B N


    All beta-adrenoceptor blocking drugs that have been described share the common property of being competitive inhibitors. They differ in their associated properties, the presence or absence of cardioselectivity, membrane stabilizing activity, and partial agonist activity. Recently some beta-adrenoceptor blocking drugs have been reported which also possess alpha-adrenoceptor blocking activity. The associated properties have been used as a basis for classifying beta-adrenoceptor blocking drugs (Fitzgerald, 1969, 1972). The presence or absence of cardioselectivity is most useful for dividing beta-adrenoceptor blocking drugs. The non-selective drugs (Division I) can be further divided according to the presence or absence of intrinsic sympathomimetic activity (ISA) and membrane stabilizing activity (Fitzgerald's groups I-IV). Group I possess both membrane activity and ISA, e.g. alprenolol, oxprenolol, group II just membrane action, e.g. propanolol, group III ISA but no membrane action, e.g. pindolol. Fitzgerald placed pindolol in group I but should be placed in group III as it possesses a high degree of beta-adrenoceptor blocking potency in relation to its membrane activity (Prichard, 1974). Finally drugs in group IV have neither ISA nor membrane action, e.g. sotalol, timolol. The cardioselective drugs (Division II) can be similarly sub-divided into groups I-IV according to the presence or absence of ISA or membrane action (Fitzgerald grouped all these together as group V). Lastly there are new beta-adrenergic receptor blocking drugs which in addition have alpha- adrenergic receptor blocking properties (Division III). PMID:26370

  3. Association between the cortisol response to opioid blockade and the Asn40Asp polymorphism at the mu-opioid receptor locus (OPRM1). (United States)

    Hernandez-Avila, Carlos A; Wand, Gary; Luo, Xingguang; Gelernter, Joel; Kranzler, Henry R


    This study examined whether a reportedly functional polymorphism in the gene encoding the mu-opioid receptor protein (A118G, which causes an Asn40Asp substitution in the receptor's extracellular domain), modifies the cortisol response to the opioid antagonist naloxone. The polymorphism occurs commonly in European Americans and some other population groups, underscoring its potential phenotypic significance. Using a balanced, within-subject design involving two test sessions over a period of 3-7 days, we examined ACTH and cortisol responses to intravenous naloxone (125 microg/kg) or placebo in 30 healthy subjects (21 males, mean age = 24.4 years). Plasma ACTH and cortisol concentrations were measured over 120 min post infusion. DNA isolated from whole blood was PCR amplified and genotyped via restriction enzyme digestion, with genotypes assigned based on agarose gel size fractionation. Subjects with one or more Asp40 alleles (n = 6; 5 heterozygotes and 1 homozygote) had significantly higher cortisol concentrations at baseline and at 15, 60, and 90 min after naloxone infusion than subjects homozygous for the Asn40 allele (n = 24). Subjects with the Asp40 allele also had a greater peak cortisol response and a greater area under the cortisol time curve than those homozygous for the Asn40 allele. There were no effects of the Asn40Asp polymorphism on plasma ACTH concentration or on self-reported anxiety or distress. These findings are consistent with recent reports showing an enhanced cortisol response to naloxone and a reduced agonist effect of morphine-6-glucuronide among subjects with the Asp40 variant. Given evidence of its pharmacological significance, the clinical relevance of this polymorphism warrants further investigation. Copyright 2003 Wiley-Liss, Inc.

  4. Excitatory amino acid receptor blockade within the caudal pressor area and rostral ventrolateral medulla alters cardiovascular responses to nucleus raphe obscurus stimulation in rats

    Directory of Open Access Journals (Sweden)

    Silva N.F.


    Full Text Available Pressor responses elicited by stimulation of the nucleus raphe obscurus (NRO depend on the integrity of the rostral ventrolateral medulla (RVLM. Therefore, to test the participation of excitatory amino acid (EAA receptors in the cardiovascular responses evoked by NRO stimulation (1 ms, 100 Hz, 40-70 µA, for 10 s, the EAA antagonist kynurenic acid (Kyn was microinjected at different sites in the ventrolateral medullar surface (2.7 nmol/200 nl of male Wistar rats (270-320 g, N = 39 and NRO stimulation was repeated. The effects of NRO stimulation were: hypertension (deltaMAP = +43 ± 1 mmHg, P<0.01, bradycardia (deltaHR = -30 ± 7 bpm, P<0.01 and apnea. Bilateral microinjection of Kyn into the RVLM, which did not change baseline parameters, almost abolished the bradycardia induced by NRO stimulation (deltaHR = -61 ± 3 before vs -2 ± 3 bpm after Kyn, P<0.01, N = 7. Unilateral microinjection of Kyn into the CVLM did not change baseline parameters or reduce the pressor response to NRO stimulation (deltaMAP = +46 ± 5 before vs +48 ± 5 mmHg after Kyn, N = 6. Kyn bilaterally microinjected into the caudal pressor area reduced blood pressure and heart rate and almost abolished the pressor response to NRO stimulation (deltaMAP = +46 ± 4 mmHg before vs +4 ± 2 mmHg after Kyn, P<0.01, N = 7. These results indicate that EAA receptors on the medullary ventrolateral surface play a role in the modulation of the cardiovascular responses induced by NRO stimulation, and also suggest that the RVLM participates in the modulation of heart rate responses and that the caudal pressor area modulates the pressor response following NRO stimulation.

  5. Blockade of GABA(A) receptors in the paraventricular nucleus of the hypothalamus attenuates voluntary ethanol intake and activates the hypothalamic-pituitary-adrenocortical axis. (United States)

    Li, Jing; Bian, Weiliang; Dave, Vaidehi; Ye, Jiang-Hong


    The paraventricular nucleus (PVN) in the hypothalamus is the main integration site that controls the hypothalamic-pituitary-adrenal (HPA) neuroendocrine stress system. Disruption of this system has been linked with alcoholism, but the specific role of the PVN has not been fully explored. Of particular interest is the ability of γ-aminobutyric acid type A receptors (GABA(A)Rs) in the PVN, to regulate ethanol self-administration behavior, as these receptors appear to play an essential role in mediating the effects of ethanol in the central nervous system and in the regulation of PVN activity. We observed that Long-Evans rats, in the intermittent access to 20% ethanol paradigm, consumed high amounts of ethanol and subsequently developed ethanol dependence. Microinjection of the GABA(A)R antagonist picrotoxin into the PVN, but not to the lateral ventricle of the brain, significantly reduced the intake of ethanol, but not the intake of sucrose. Picrotoxin-induced reduction was mimicked by another GABA(A)R antagonist bicuculline but was attenuated by the GABA(A)R agonist muscimol. Moreover, increased ethanol consumption was associated with lowered blood corticosterone levels, indicating a blunted HPA signaling, which was reversed by intra-PVN injection of picrotoxin, as indicated by the increased Fos immunostaining-positive cells in the PVN and the increased blood corticosterone levels. Taken together, our data provide evidence that in ethanol-dependent rats, the function of GABA(A)Rs in the PVN is upregulated, leading to a dampened HPA system. Moreover, it demonstrates that the GABA(A)R antagonists normalize HPA axis signaling and reduce excessive ethanol drinking. Therefore, drugs targeting GABA(A)Rs may be beneficial for alcoholics. © 2011 The Authors, Addiction Biology © 2011 Society for the Study of Addiction.

  6. Permanent Distal Occlusion of Middle Cerebral Artery in Rat Causes Local Increased ETB, 5-HT1B and AT1 Receptor-Mediated Contractility Downstream of Occlusion

    DEFF Research Database (Denmark)

    Rasmussen, Marianne N P; Hornbak, Malene; Larsen, Stine S


    a model of permanent distal occlusion of rat middle cerebral arteries, we investigated whether there was a regional difference in receptor-mediated contractility of segments located upstream and downstream of the occlusion site. The contractile response to endothelin, angiotensin and 5-hydroxytryptamine...... receptor stimulation was studied by sensitive wire myograph. Results: Only downstream segments exhibited an augmented contractile response to stimulation with each of the three ligands, with the response towards sarafotoxin 6c being especially augmented compared to sham, upstream and contralateral controls...... occlusion without significant visible infarct resulted in locally increased ETB, angiotensin type 1 and 5-hydroxytryptamine 1B receptor-mediated contractile responses only in segments located downstream of the occlusion site. This suggests lack of wall stress as an initiating trigger leading to regulation...

  7. Angiotensin AT1-receptor blockers and cerebrovascular protection: do they actually have a cutting edge over angiotensin-converting enzyme inhibitors?

    DEFF Research Database (Denmark)

    Oprisiu-Fournier, Roxana; Faure, Sébastien; Mazouz, Hakim


    First, an update of the vascular systemic and tissue renin-angiotensin-aldosterone system is provided to explain how it is regulated at the systemic and tissue levels, and how many angiotensin peptides and receptors can be modulated by the various antihypertensive drugs. Second, experimental data...... AT2 receptors are overexpressed) or by directly increasing neuronal resistance to anoxia. Third, we review most of the large primary and secondary stroke prevention trials as well as the ACCESS acute stroke trial in which antihypertensive drugs were evaluated. With the exception of the secondary...

  8. Frontal fasciculi and psychotic symptoms in antipsychotic-naive patients with schizophrenia before and after 6 weeks of selective dopamine D2/3 receptor blockade

    DEFF Research Database (Denmark)

    Ebdrup, Bjørn H; Raghava, Jayachandra M; Nielsen, Mette Ødegaard


    BACKGROUND: Psychotic symptoms are core clinical features of schizophrenia. We tested recent hypotheses proposing that psychotic, or positive, symptoms stem from irregularities in long-range white matter tracts projecting into the frontal cortex, and we predicted that selective dopamine D2/3 rece......, and psychotic symptoms appeared specifically associated with frontal fasciculi integrity. Six weeks of amisulpride treatment normalized white matter. Potential remyelinating effects of dopamine D2/3 receptor antagonism warrant further clarification.......BACKGROUND: Psychotic symptoms are core clinical features of schizophrenia. We tested recent hypotheses proposing that psychotic, or positive, symptoms stem from irregularities in long-range white matter tracts projecting into the frontal cortex, and we predicted that selective dopamine D2...... corticospinal tract (CT). Fractional anisotropy in the right ATR correlated with positive symptoms (z = 2.64, p= 0.008). The ROI analyses showed significant associations between positive symptoms and FA of the frontal fasciculi, specifically the right arcuate fasciculus (z = 2.83, p= 0.005) and right superior...

  9. Sex Differences in Immunology: More Severe Development of Experimental Pulmonary Hypertension in Male Rats Exposed to Vascular Endothelial Growth Factor Receptor Blockade

    Directory of Open Access Journals (Sweden)

    Julien Guihaire


    Full Text Available Background. The epidemiology of pulmonary hypertension (PH is characterized by a female preponderance, whereas males share higher severity of the disease. Objective. To compare the severity of experimental PH between male and female athymic rats. Methods. PH was induced in 11 male and 11 female athymic rats (resp., SU_M and SU_F groups using an inhibitor of VEGF-receptors I and II, semaxanib (40 mg/kg. After 28 days, right ventricular (RV remodeling, systolic function, and hemodynamics were measured using echocardiography and a pressure-volume admittance catheter. Morphometric analyses of lung vasculature and RV myocardium were performed. Results. Four weeks after semaxanib injection, RV end-systolic pressure was higher in SU_M than in SU_F. Males developed marked RV enlargement and systolic dysfunction compared to females. Impairment of RV-PA coupling efficiency was observed only in SU_M. The smooth muscle cells of the pulmonary arteries switched from a contractile state to a dedifferentiated state only in males. Conclusions. Female athymic rats were protected against the development of severe PH. RV-PA coupling was preserved in females through limitation of pulmonary artery muscularization. Control of smooth muscle cells plasticity may be a promising therapeutic approach to reverse established vascular remodeling in PH patients.

  10. Functional enhancement of AT1R potency in the presence of the TPαR is revealed by a comprehensive 7TM receptor co-expression screen

    DEFF Research Database (Denmark)

    Hansen, Jonas Tind; Lyngsø, Christina; Speerschneider, Tobias


    Functional cross-talk between seven transmembrane (7TM) receptors can dramatically alter their pharmacological properties, both in vitro and in vivo. This represents an opportunity for the development of novel therapeutics that potentially target more specific biological effects while causing few...

  11. Dopamine receptor blockade attenuates the general incentive motivational effects of noncontingently delivered rewards and reward-paired cues without affecting their ability to bias action selection. (United States)

    Ostlund, Sean B; Maidment, Nigel T


    Environmental cues affect our behavior in a variety of ways. Despite playing an invaluable role in guiding our daily activities, such cues also appear to trigger the harmful, compulsive behaviors that characterize addiction and other disorders of behavioral control. In instrumental conditioning, rewards and reward-paired cues bias action selection and invigorate reward-seeking behaviors, and appear to do so through distinct neurobehavioral processes. Although reward-paired cues are known to invigorate performance through a dopamine-dependent incentive motivational process, it is not known if dopamine also mediates the influence of rewards and reward-paired cues over action selection. The current study contrasted the effects of systemic administration of the nonspecific dopamine receptor antagonist flupentixol on response invigoration and action bias in Pavlovian-instrumental transfer, a test of cue-elicited responding, and in instrumental reinstatement, a test of noncontingent reward-elicited responding. Hungry rats were trained on two different stimulus-outcome relationships (eg, tone-grain pellets and noise-sucrose solution) and two different action-outcome relationships (eg, left press-grain and right press-sucrose). At test, we found that flupentixol pretreatment blocked the response invigoration generated by the cues but spared their ability to bias action selection to favor the action whose outcome was signaled by the cue being presented. The response-biasing influence of noncontingent reward deliveries was also unaffected by flupentixol. Interestingly, although flupentixol had a modest effect on the immediate response invigoration produced by those rewards, it was particularly potent in countering the lingering enhancement of responding produced by multiple reward deliveries. These findings indicate that dopamine mediates the general incentive motivational effects of noncontingent rewards and reward-paired cues but does not support their ability to bias

  12. Different Molecular/Behavioral Endophenotypes in C57BL/6J Mice Predict the Impact of OX1 Receptor Blockade on Binge-Like Ethanol Intake

    Directory of Open Access Journals (Sweden)

    Manuel Alcaraz-Iborra


    Full Text Available Ethanol (EtOH research has focused on stages of dependence. It is of paramount importance to more deeply understand the neurobehavioral factors promoting increased risk for EtOH binge drinking during the early stages of the addiction cycle. The first objective of this study was to evaluate whether C57BL/6J mice showing high drinking in the dark (DID exhibit neurobehavioral traits known to contribute to EtOH binge-drinking disorders. Comparing high vs. low drinkers (HD/LD, we evaluated different types of basal anxiety-like responses, EtOH preference and sensitivity to the reinforcing properties of EtOH, and basal mRNA expression of the OX1/OX2 receptors (OX1r/OX2r within the prefrontal cortex (PFC and the nucleus accumbens (NAcc. Additionally, we tested binge drinking by LD/HD in response to a selective OX1r antagonist following intermittent episodes of DID (iDID. We report that DID consistently segregates two neurobehavioral endophenotypes, HD vs. LD, showing differences in neophobia and/or impulsivity/compulsivity traits. Additionally, HD mice show decreased basal OX1r and OX2r mRNA expression within the NAcc and elevated OX1r within the PFC. Exposure to several intermittent episodes of EtOH DID triggered a rapid increase in EtOH intake over time in LD mice matching that observed in HD mice. Despite HD/LD endophenotypes did not show differences in EtOH intake, they still predicted the response to a pharmacological challenge with a selective OX1r antagonist. The present data underscore the relevance of HD/LD endophenotypes stemming from DID procedures for exploring neurobehavioral processes underlying the early stages of the addiction cycle and EtOH binge-drinking disorders.

  13. Molecular Understanding of the Activation of CB1 and Blockade of TRPV1 Receptors: Implications for Novel Treatment Strategies in Osteoarthritis

    Directory of Open Access Journals (Sweden)

    Jakub Mlost


    Full Text Available Osteoarthritis (OA is a joint disease in which cartilage degenerates as a result of mechanical and biochemical changes. The main OA symptom is chronic pain involving both peripheral and central mechanisms of nociceptive processing. Our previous studies have implicated the benefits of dual- over single-acting compounds interacting with the endocannabinoid system (ECS in OA treatment. In the present study, we focused on the specific molecular alterations associated with pharmacological treatment. OA was induced in Wistar rats by intra-articular injection of 3 mg of monoiodoacetate (MIA. Single target compounds (URB597, an FAAH inhibitor, and SB366791, a TRPV1 antagonist and a dual-acting compound OMDM198 (FAAH inhibitor/TRPV1 antagonist were used in the present study. At day 21 post-MIA injection, rats were sacrificed 1 h after i.p. treatment, and changes in mRNA expression were evaluated in the lumbar spinal cord by RT-qPCR. Following MIA administration, we observed 2-4-fold increase in mRNA expression of targeted receptors (Cnr1, Cnr2, and Trpv1, endocannabinoid degradation enzymes (Faah, Ptgs2, and Alox12, and TRPV1 sensitizing kinases (Mapk3, Mapk14, Prkcg, and Prkaca. OMDM198 treatment reversed some of the MIA effects on the spinal cord towards intact levels (Alox12, Mapk14, and Prkcg. Apparent regulation of ECS and TRPV1 in response to pharmacological intervention is a strong justification for novel ECS-based multi-target drug treatment in OA.

  14. Proton pump inhibitor use and fracture risk - effect modification by histamine H1 receptor blockade. Observational case-control study using National Prescription Data. (United States)

    Abrahamsen, Bo; Vestergaard, Peter


    It remains unknown why proton pump inhibitor (PPI) use may be associated with risk of osteoporotic fractures; evidence of direct effects on calcium absorption or on the osteoclast in humans is weak or absent. However, the ensuing increased gastrin levels may cause histamine production through hypertrophy of gastric enterochromaffin like cells, which could lead to bone loss. We speculated that H1 receptor antagonists (H1RA) used for allergies would then reduce the effect of PPI on bone. We therefore conducted a register-based case-control study comprising 124,655 patients with hospital treated fractures, who were matched 3:1 with non fracture control subjects of the same age and gender. Use of prescription medications was retrieved from the National Prescription Database and data was analyzed using conditional logistic regression analysis. We observed a significant interaction between PPI and H1RA use on fracture risk in general (adjusted OR 0.92, 95% CI 0.87-0.98) though not on hip fracture risk (adjusted OR 0.99, 95% CI 0.85-1.16). There was a significant modification of the interaction by age (pfracture categories). As previously shown, fracture risk was higher in PPI users both for fractures in general and for hip fractures. Irrespective of PPI use, H1RA users had lower risk of hip fractures than non-users (adjusted OR 0.86, 95% CI 0.79-0.93). This short report suggests that the effects of PPI on bone could be driven by in part by increased histamine release as the increased fracture risk can be modified by H1RA. © 2013.

  15. Different Molecular/Behavioral Endophenotypes in C57BL/6J Mice Predict the Impact of OX1 Receptor Blockade on Binge-Like Ethanol Intake (United States)

    Alcaraz-Iborra, Manuel; Navarrete, Francisco; Rodríguez-Ortega, Elisa; de la Fuente, Leticia; Manzanares, Jorge; Cubero, Inmaculada


    Ethanol (EtOH) research has focused on stages of dependence. It is of paramount importance to more deeply understand the neurobehavioral factors promoting increased risk for EtOH binge drinking during the early stages of the addiction cycle. The first objective of this study was to evaluate whether C57BL/6J mice showing high drinking in the dark (DID) exhibit neurobehavioral traits known to contribute to EtOH binge-drinking disorders. Comparing high vs. low drinkers (HD/LD), we evaluated different types of basal anxiety-like responses, EtOH preference and sensitivity to the reinforcing properties of EtOH, and basal mRNA expression of the OX1/OX2 receptors (OX1r/OX2r) within the prefrontal cortex (PFC) and the nucleus accumbens (NAcc). Additionally, we tested binge drinking by LD/HD in response to a selective OX1r antagonist following intermittent episodes of DID (iDID). We report that DID consistently segregates two neurobehavioral endophenotypes, HD vs. LD, showing differences in neophobia and/or impulsivity/compulsivity traits. Additionally, HD mice show decreased basal OX1r and OX2r mRNA expression within the NAcc and elevated OX1r within the PFC. Exposure to several intermittent episodes of EtOH DID triggered a rapid increase in EtOH intake over time in LD mice matching that observed in HD mice. Despite HD/LD endophenotypes did not show differences in EtOH intake, they still predicted the response to a pharmacological challenge with a selective OX1r antagonist. The present data underscore the relevance of HD/LD endophenotypes stemming from DID procedures for exploring neurobehavioral processes underlying the early stages of the addiction cycle and EtOH binge-drinking disorders. PMID:29066961

  16. The blockade of the transient receptor potential vanilloid type 1 and fatty acid amide hydrolase decreases symptoms and central sequelae in the medial prefrontal cortex of neuropathic rats

    Directory of Open Access Journals (Sweden)

    Di Marzo Vincenzo


    Full Text Available Abstract Background Neuropathic pain is a chronic disease resulting from dysfunction within the "pain matrix". The basolateral amygdala (BLA can modulate cortical functions and interactions between this structure and the medial prefrontal cortex (mPFC are important for integrating emotionally salient information. In this study, we have investigated the involvement of the transient receptor potential vanilloid type 1 (TRPV1 and the catabolic enzyme fatty acid amide hydrolase (FAAH in the morphofunctional changes occurring in the pre-limbic/infra-limbic (PL/IL cortex in neuropathic rats. Results The effect of N-arachidonoyl-serotonin (AA-5-HT, a hybrid FAAH inhibitor and TPRV1 channel antagonist, was tested on nociceptive behaviour associated with neuropathic pain as well as on some phenotypic changes occurring on PL/IL cortex pyramidal neurons. Those neurons were identified as belonging to the BLA-mPFC pathway by electrical stimulation of the BLA followed by hind-paw pressoceptive stimulus application. Changes in their spontaneous and evoked activity were studied in sham or spared nerve injury (SNI rats before or after repeated treatment with AA-5-HT. Consistently with the SNI-induced changes in PL/IL cortex neurons which underwent profound phenotypic reorganization, suggesting a profound imbalance between excitatory and inhibitory responses in the mPFC neurons, we found an increase in extracellular glutamate levels, as well as the up-regulation of FAAH and TRPV1 in the PL/IL cortex of SNI rats. Daily treatment with AA-5-HT restored cortical neuronal activity, normalizing the electrophysiological changes associated with the peripheral injury of the sciatic nerve. Finally, a single acute intra-PL/IL cortex microinjection of AA-5-HT transiently decreased allodynia more effectively than URB597 or I-RTX, a selective FAAH inhibitor or a TRPV1 blocker, respectively. Conclusion These data suggest a possible involvement of endovanilloids in the cortical

  17. Increased perfusion pressure enhances the expression of endothelin (ETB) and angiotensin II (AT1, AT2) receptors in rat mesenteric artery smooth muscle cells

    DEFF Research Database (Denmark)

    Lindstedt, Isak; Xu, Cang-Bao; Zhang, Yaping


    and luminally perfused in a perfusion chamber. After either exposure to no ("organ culture" (0 mmHg)), normal (85/75 mmHg) or high pressure (160/150 mmHg) at constant flow for 1-17 h, the vessel segments were snap frozen and real-time polymerase chain reaction was performed to quantify the ET- and AT-receptor m...

  18. Sodium intake, RAAS-blockade and progressive renal disease

    NARCIS (Netherlands)

    de Borst, Martin H; Navis, Gerjan

    Pharmacological blockade of the renin-angiotensin-aldosterone system (RAAS) by angiotensin converting enzyme inhibitors or angiotensin receptor blockers is the current standard treatment to prevent progressive renal function loss in patients with chronic kidney disease. Yet in many patients the

  19. Discovery of novel, potent and low-toxicity angiotensin II receptor type 1 (AT1) blockers: Design, synthesis and biological evaluation of 6-substituted aminocarbonyl benzimidazoles with a chiral center. (United States)

    Han, Xiao-Feng; He, Xing; Wang, Miao; Xu, Di; Hao, Li-Ping; Liang, Ai-Hua; Zhang, Jun; Zhou, Zhi-Ming


    Novel angiotensin II receptor type 1 (AT1) blockers bearing 6-substituted carbamoyl benzimidazoles with a chiral center were designed and synthesized as the first step to develop new antihypertensive agents and understand their pharmacodynamic and pharmacokinetic properties. The newly synthesized compounds were tested for their potential ability to displace [(125)I] Sar(1) Ile(8)-Ang II, which was specifically bound to human AT1 receptor. Radioligand binding assays revealed nanomolar affinity in several compounds under study. The IC50 values of nine ligands were higher than those of Losartan. The screening of decreased blood pressure in spontaneous hypertensive rats displayed that compound 8S (IC₅₀ = 5.0 nM) was equipotent with Losartan, whereas compounds 13R (IC₅₀ = 7.3 nM), 14R (IC₅₀ = 6.3 nM), and 14S (IC₅₀ = 3.5 nM) were slightly ahead of Losartan, and the most significant activity was demonstrated by compound 8R (IC₅₀ = 1.1 nM). Candidate 8R was identified for its excellent efficacy in antihypertension and fairly low toxicity based on plasma analyses, toxicology studies, and chronic oral tests. Finally, compound 8R exhibited strong and multiple interactions with target active sites of the theoretical AT1 receptor model in docking study. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  20. Elevated N-terminal pro-brain natriuretic peptide levels predict an enhanced anti-hypertensive and anti-proteinuric benefit of dietary sodium restriction and diuretics, but not angiotensin receptor blockade, in proteinuric renal patients

    NARCIS (Netherlands)

    Slagman, Maartje C. J.; Waanders, Femke; Vogt, Liffert; Damman, Kevin; Hemmelder, Marc; Navis, Gerjan; Laverman, Gozewijn D.


    Background. Renin angiotensin aldosterone system (RAAS) blockade only partly reduces blood pressure, proteinuria and renal and cardiovascular risk in chronic kidney disease (CKD) but often requires sodium targeting [i.e. low sodium diet (LS) and/or diuretics] for optimal efficacy. However, both

  1. Elevated N-terminal pro-brain natriuretic peptide levels predict an enhanced anti-hypertensive and anti-proteinuric benefit of dietary sodium restriction and diuretics, but not angiotensin receptor blockade, in proteinuric renal patients

    NARCIS (Netherlands)

    Slagman, Maartje C. J.; Waanders, Femke; Vogt, Liffert; Damman, Kevin; Hemmelder, Marc; Navis, Gerjan; Laverman, Gozewijn D.

    Background. Renin angiotensin aldosterone system (RAAS) blockade only partly reduces blood pressure, proteinuria and renal and cardiovascular risk in chronic kidney disease (CKD) but often requires sodium targeting [i.e. low sodium diet (LS) and/or diuretics] for optimal efficacy. However, both


    Wang, Zheng; Zeng, Chunyu; Villar, Van Anthony M.; Chen, Shi-You; Konkalmatt, Prasad; Wang, Xiaoyan; Asico, Laureano D.; Jones, John E.; Yang, Yu; Sanada, Hironobu; Felder, Robin A.; Eisner, Gilbert M.; Weir, Matthew R.; Armando, Ines; Jose, Pedro A.


    The influence of a single gene on the etiology of essential hypertension may be difficult to ascertain, unless the gene interacts with other genes that are germane to blood pressure regulation. G protein-coupled receptor kinase type 4 (GRK4) is one such gene. We have reported that the expression of its variant hGRK4γ142V in mice results in hypertension due to impaired dopamine D1 receptor (D1R). Signaling through D1R and angiotensin II type I receptor (AT1R) reciprocally modulates renal sodium excretion and blood pressure. Here, we demonstrate the ability of the hGRK4γ142V to increase the expression and activity of the AT1R. We show that hGRK4γ142V phosphorylates histone deacetylase type 1 and promotes its nuclear export to the cytoplasm, resulting in increased AT1R expression and greater pressor response to angiotensin II. AT1R blockade and the deletion of the Agtr1a gene normalize the hypertension in hGRK4γ142V mice. These findings illustrate the unique role of GRK4 by targeting receptors with opposite physiological activity for the same goal of maintaining blood pressure homeostasis, and thus making the GRK4 a relevant therapeutic target to control blood pressure. PMID:26667412

  3. Restoration of HBV-specific CD8+ T cell function by PD-1 blockade in inactive carrier patients is linked to T cell differentiation. (United States)

    Bengsch, Bertram; Martin, Bianca; Thimme, Robert


    The upregulation of several inhibitory signalling pathways by exhausted HBV-specific CD8+ T cells in chronic infection is thought to contribute to viral persistence. Blockade of inhibitory receptors to reinvigorate exhausted T cell function is a promising novel therapeutic approach. However, little information is available regarding the relative contribution of individual inhibitory pathways to HBV-specific CD8+ T cell failure and the impact of inhibitory receptor blockade on restoration of T cell function in chronic HBV. 98 HLA-A2+ chronically infected patients were analysed ex vivo for HBV-specific CD8+ T cell responses, the expression of multiple inhibitory receptors and T cell differentiation markers. The effects of inhibitory receptor blockade targeting PD-1, 2B4, Tim-3, CTLA-4, and BTLA were assessed in vitro. In our cohort, ex vivo HBV-specific CD8+ T cell responses were identified preferentially in HBeAg patients with low ALT and low viral load (inactive carriers). We observed a clear hierarchy of inhibitory receptor expression dominated by PD-1. The response to inhibitory receptor blockade was heterogeneous. Compared to the blockade of other inhibitory receptors, blockade of the PD-1 pathway resulted in the strongest increase in function. Of note, a positive effect of PD-1 blockade was linked to intermediate T cell differentiation. Despite the expression of multiple inhibitory receptors by HBV-specific CD8+ T cells, expression and response to blockade was dominated by PD-1. However, PD-1 expression did not predict response to blockade. Rather, response to blockade was associated with intermediate T cell differentiation. These findings have important implications for our understanding of inhibitory receptor blockade as a novel therapeutic strategy. Copyright © 2014. Published by Elsevier B.V.

  4. Renin activates PI3K-Akt-eNOS signalling through the angiotensin AT1 and Mas receptors to modulate central blood pressure control in the nucleus tractus solitarii (United States)

    Cheng, Wen-Han; Lu, Pei-Jung; Hsiao, Michael; Hsiao, Chun-Hui; Ho, Wen-Yu; Cheng, Pei-Wen; Lin, Chia-Te; Hong, Ling-Zong; Tseng, Ching-Jiunn


    BACKGROUND AND PURPOSE The renin-angiotensin system (RAS) is critical for the control of blood pressure by the CNS. Recently, direct renin inhibitors were approved as antihypertensive agents. However, the signalling mechanism of renin, which regulates blood pressure in the nucleus tractus solitarii (NTS) remains unclear. Here we have investigated the signalling pathways involved in renin-mediated blood pressure regulation, at the NTS. EXPERIMENTAL APPROACH Depressor responses to renin microinjected into the NTS of Wistar-Kyoto rats were elicited in the absence and presence of the endothelial nitric oxide synthase (eNOS)-specific inhibitor, N(5)-(-iminoethyl)-L-ornithine, Akt inhibitor IV and LY294002, a PI3K inhibitor and GP antagonist-2A [Gq inhibitor]. Lisinopril (angiotensin converting enzyme inhibitor), losartan, valsartan (angiotensin AT1 receptor antagonists), D-Ala7-Ang-(1-7) (angiotensin-(1-7) receptor antagonist) were used to study the involvement of RAS on renin-induced depressor effects. KEY RESULTS Microinjection of renin into the NTS produced a prominent depressor effect and increased NO production. Pretreatment with Gq-PI3K-Akt-eNOS pathway-specific inhibitors significantly attenuated the depressor response evoked by renin. Immunoblotting and immunohistochemical studies further showed that inhibition of PI3K significantly blocked renin-induced eNOS-Ser117 and Akt-Ser473 phosphorylation in situ. In addition, pre-treatment of the NTS with RAS inhibitors attenuated the vasodepressor effects evoked by renin. Microinjection of renin also increased Ras activation in the NTS. CONCLUSIONS AND IMPLICATIONS Taken together, these results suggest renin modulated blood pressure at the NTS by AT1 and Mas receptor-mediated activation of Gq and Ras to evoke PI3K-Akt-eNOS signalling. PMID:22224457

  5. Activation of microglial cells triggers a release of brain-derived neurotrophic factor (BDNF) inducing their proliferation in an adenosine A2A receptor-dependent manner: A2A receptor blockade prevents BDNF release and proliferation of microglia (United States)


    Background Brain-derived neurotrophic factor (BDNF) has been shown to control microglial responses in neuropathic pain. Since adenosine A2A receptors (A2ARs) control neuroinflammation, as well as the production and function of BDNF, we tested to see if A2AR controls the microglia-dependent secretion of BDNF and the proliferation of microglial cells, a crucial event in neuroinflammation. Methods Murine N9 microglial cells were challenged with lipopolysaccharide (LPS, 100 ng/mL) in the absence or in the presence of the A2AR antagonist, SCH58261 (50 nM), as well as other modulators of A2AR signaling. The BDNF cellular content and secretion were quantified by Western blotting and ELISA, A2AR density was probed by Western blotting and immunocytochemistry and cell proliferation was assessed by BrdU incorporation. Additionally, the A2AR modulation of LPS-driven cell proliferation was also tested in primary cultures of mouse microglia. Results LPS induced time-dependent changes of the intra- and extracellular levels of BDNF and increased microglial proliferation. The maximal LPS-induced BDNF release was time-coincident with an LPS-induced increase of the A2AR density. Notably, removing endogenous extracellular adenosine or blocking A2AR prevented the LPS-mediated increase of both BDNF secretion and proliferation, as well as exogenous BDNF-induced proliferation. Conclusions We conclude that A2AR activation plays a mandatory role controlling the release of BDNF from activated microglia, as well as the autocrine/paracrine proliferative role of BDNF. PMID:23363775

  6. Dual Blockade of the Renin-angiotensin-aldosterone System in Type 2 Diabetic Kidney Disease

    Directory of Open Access Journals (Sweden)

    Yan-Huan Feng


    Full Text Available Objective: To examine the efficacy and safety of dual blockade of the renin-angiotensin-aldosterone system (RAAS among patients with type 2 diabetic kidney disease. Data Sources: We searched the major literature repositories, including the Cochrane Central Register of Controlled Trials, MEDLINE and EMBASE, for randomized clinical trials published between January 1990 and October 2015 that compared the efficacy and safety of the use of dual blockade of the RAAS versus the use of monotherapy, without applying any language restrictions. Keywords for the searches included "diabetic nephropathy," "chronic kidney disease," "chronic renal insufficiency," "diabetes mellitus," "dual therapy," "combined therapy," "dual blockade," "renin-angiotensin system," "angiotensin-converting enzyme inhibitor," "angiotensin-receptor blocker," "aldosterone blockade," "selective aldosterone blockade," "renin inhibitor," "direct renin inhibitor," "mineralocorticoid receptor blocker," etc. Study Selection: The selected articles were carefully reviewed. We excluded randomized clinical trials in which the kidney damage of patients was related to diseases other than diabetes mellitus. Results: Combination treatment with an angiotensin-converting enzyme inhibitor supplemented by an angiotensin II receptor blocking agent is expected to provide a more complete blockade of the RAAS and a better control of hypertension. However, existing literature has presented mixed results, in particular, related to patient safety. In view of this, we conducted a comprehensive literature review in order to explain the rationale for dual blockade of the RAAS, and to discuss the pros and cons. Conclusions: Despite the negative results of some recent large-scale studies, it may be immature to declare that the dual blockade is a failure because of the complex nature of the RAAS surrounding its diversified functions and utility. Further trials are warranted to study the combination therapy as an

  7. A2aR antagonists: Next generation checkpoint blockade for cancer immunotherapy

    Directory of Open Access Journals (Sweden)

    Robert D. Leone


    Full Text Available The last several years have witnessed exciting progress in the development of immunotherapy for the treatment of cancer. This has been due in great part to the development of so-called checkpoint blockade. That is, antibodies that block inhibitory receptors such as CTLA-4 and PD-1 and thus unleash antigen-specific immune responses against tumors. It is clear that tumors evade the immune response by usurping pathways that play a role in negatively regulating normal immune responses. In this regard, adenosine in the immune microenvironment leading to the activation of the A2a receptor has been shown to represent one such negative feedback loop. Indeed, the tumor microenvironment has relatively high concentrations of adenosine. To this end, blocking A2a receptor activation has the potential to markedly enhance anti-tumor immunity in mouse models. This review will present data demonstrating the ability of A2a receptor blockade to enhance tumor vaccines, checkpoint blockade and adoptive T cell therapy. Also, as several recent studies have demonstrated that under certain conditions A2a receptor blockade can enhance tumor progression, we will also explore the complexities of adenosine signaling in the immune response. Despite important nuances to the A2a receptor pathway that require further elucidation, studies to date strongly support the development of A2a receptor antagonists (some of which have already been tested in phase III clinical trials for Parkinson Disease as novel modalities in the immunotherapy armamentarium.

  8. Hydronephrosis alters cardiac ACE2 and Mas receptor expression in mice. (United States)

    Zhang, Yanling; Ma, Lulu; Wu, Junyan; Chen, Tingting


    Hydronephrosis is characterized by substantial loss of tubules and affects renin secretion in the kidney. However, whether alterations of angiotensin-converting enzyme (ACE), ACE2 and Mas receptor in the heart are observed in hydronephrosis is unknown. Thus, we assessed these components in hydronephrotic mice treated with AT1 receptor blockade and ACE inhibitor. Hydronephrosis was induced by left ureteral ligation in Balb/C mice except sham-operated animals. The levels of cardiac ACE, ACE2 and Mas receptor were measured after treatment of losartan or enalapril. Hydronephrosis led to an increase of ACE level and a decrease of ACE2 and Mas receptor in the heart. Losartan decreased cardiac ACE level, but ACE2 and Mas receptor levels significantly increased in hydronephrotic mice (p Mas receptor in the heart. Plasma renin activity (PRA) and Ang II decreased in hydronephrotic mice, but significantly increased after treatment with losartan or enalapril. Hydronephrosis increased cardiac ACE and suppressed ACE2 and Mas receptor levels. AT1 blockade caused sustained activation of cardiac ACE2 and Mas receptor, but ACE inhibitor had the limitation of such activation of Mas receptor in hydronephrotic animals. © The Author(s) 2015.

  9. Giant, dopamine secreting thoracoabdominal neuroblastoma in a 2-year-old: rapid preoperative blockade with labetalol. (United States)

    Pappas, Lisbeth; Shamberger, Robert C; Seefelder, Christian


    Neuroblastomas secreting large amounts of catecholamines may require preoperative antihypertensive treatment to avoid intraoperative hypertensive crises as do pheochromocytomas. This is typically achieved with alpha-adrenergic followed if necessary by beta-adrenergic receptor blockade. Because of its predominant beta-blockade, labetalol as a combined alpha-adrenergic and beta-adrenergic receptor antagonist is relatively contraindicated as sole and first agent in pheochromocytomas releasing epinephrine and norepinephrine. We report successful monotherapy with labetalol over 24 hours in a 2-year-old child with a giant thoracoabdominal neuroblastoma and predominant dopamine secretion.

  10. Pharmacologic perspectives of functional selectivity by the angiotensin II type 1 receptor

    DEFF Research Database (Denmark)

    Aplin, Mark; Christensen, Gitte Lund; Hansen, Jakob Lerche


    such as aldosterone secretion, vasoconstriction, and detrimental cardiac hypertrophy are known to result from G protein-dependent or -independent signal transduction, whereas mechanisms have been connected with more adaptive cardiac cell survival, migration, and regeneration phenotypes. Selective blockade of G......The angiotensin II type 1 (AT(1)) receptor plays a key role in cardiovascular pathophysiology, and it is a major pharmacologic target in the treatment of many cardiovascular disorders. However, AT(1) receptor activation is also involved in adaptive responses to altered hemodynamic demands...

  11. No effect of angiotensin II AT(2)-receptor antagonist PD 123319 on cerebral blood flow autoregulation

    DEFF Research Database (Denmark)

    Estrup, T M; Paulson, O B; Strandgaard, S


    Blockade of the renin-angiotensin system with angiotensin-converting enzyme inhibitors (ACE-I) or angiotensin AT1-receptor antagonists shift the limits of autoregulation of cerebral blood flow (CBF) towards lower blood pressure (BP). The role of AT2-receptors in the regulation of the cerebral...... circulation is uncertain. Hence, the present study investigated the effect on CBF autoregulation of blocking of angiotensin AT2-receptors with PD 123319 in spontaneously hypertensive rats (SHR). Anaesthetised and ventilated SHR were given PD 123319, 0.36 mg/kg/min, intravenously, and compared with a control...

  12. Endothelial Microparticles From Acute Coronary Syndrome Patients Induce Premature Coronary Artery Endothelial Cell Aging and Thrombogenicity: Role of the Ang II/AT1 Receptor/NADPH Oxidase-Mediated Activation of MAPKs and PI3-Kinase Pathways. (United States)

    Abbas, Malak; Jesel, Laurence; Auger, Cyril; Amoura, Lamia; Messas, Nathan; Manin, Guillaume; Rumig, Cordula; León-González, Antonio J; Ribeiro, Thais P; Silva, Grazielle C; Abou-Merhi, Raghida; Hamade, Eva; Hecker, Markus; Georg, Yannick; Chakfe, Nabil; Ohlmann, Patrick; Schini-Kerth, Valérie B; Toti, Florence; Morel, Olivier


    Microparticles (MPs) have emerged as a surrogate marker of endothelial dysfunction and cardiovascular risk. This study examined the potential of MPs from senescent endothelial cells (ECs) or from patients with acute coronary syndrome (ACS) to promote premature EC aging and thrombogenicity. Primary porcine coronary ECs were isolated from the left circumflex coronary artery. MPs were prepared from ECs and venous blood from patients with ACS (n=30) and from healthy volunteers (n=4) by sequential centrifugation. The level of endothelial senescence was assessed as senescence-associated β-galactosidase activity using flow cytometry, oxidative stress using the redox-sensitive probe dihydroethidium, tissue factor activity using an enzymatic Tenase assay, the level of target protein expression by Western blot analysis, platelet aggregation using an aggregometer, and shear stress using a cone-and-plate viscometer. Senescence, as assessed by senescence-associated β-galactosidase activity, was induced by the passaging of porcine coronary artery ECs from passage P1 to P4, and was associated with a progressive shedding of procoagulant MPs. Exposure of P1 ECs to MPs shed from senescent P3 cells or circulating MPs from ACS patients induced increased senescence-associated β-galactosidase activity, oxidative stress, early phosphorylation of mitogen-activated protein kinases and Akt, and upregulation of p53, p21, and p16. Ex vivo, the prosenescent effect of circulating MPs from ACS patients was evidenced only under conditions of low shear stress. Depletion of endothelial-derived MPs from ACS patients reduced the induction of senescence. Prosenescent MPs promoted EC thrombogenicity through tissue factor upregulation, shedding of procoagulant MPs, endothelial nitric oxide synthase downregulation, and reduced nitric oxide-mediated inhibition of platelet aggregation. These MPs exhibited angiotensin-converting enzyme activity and upregulated AT1 receptors and angiotensin

  13. Influence of beta blockade on gastric acid secretion and changes in gastric mucosal blood flow before and after parietal cell vagotomy in dogs and man

    DEFF Research Database (Denmark)

    Hovendal, C P; Bech, K; Bekker, C


    -Adrenergic blockade had no effect on pentagastrin-stimulated gastric acid secretion before PCV, but after PCV beta blockade caused a modest increase in acid secretion, mediated mainly by the beta 2 receptors. A similar trend was seen in man. A marked increase in mucosal blood flow occurred 30 min after propranolol...

  14. Clinical utility of sympathetic blockade in cardiovascular disease management. (United States)

    Park, Chan Soon; Lee, Hae-Young


    A dysregulated sympathetic nervous system is a major factor in the development and progression of cardiovascular disease; thus, understanding the mechanism and function of the sympathetic nervous system and appropriately regulating sympathetic activity to treat various cardiovascular diseases are crucial. Areas covered: This review focused on previous studies in managing hypertension, atrial fibrillation, coronary artery disease, heart failure, and perioperative management with sympathetic blockade. We reviewed both pharmacological and non-pharmacological management. Expert commentary: Chronic sympathetic nervous system activation is related to several cardiovascular diseases mediated by various pathways. Advancement in measuring sympathetic activity makes visualizing noninvasively and evaluating the activation level even in single fibers possible. Evidence suggests that sympathetic blockade still has a role in managing hypertension and controlling the heart rate in atrial fibrillation. For ischemic heart disease, beta-adrenergic receptor antagonists have been considered a milestone drug to control symptoms and prevent long-term adverse effects, although its clinical implication has become less potent in the era of successful revascularization. Owing to pathologic involvement of sympathetic nervous system activation in heart failure progression, sympathetic blockade has proved its value in improving the clinical course of patients with heart failure.

  15. Rydberg Quantum Gates Free from Blockade Error (United States)

    Shi, Xiao-Feng


    Accurate quantum gates are basic elements for building quantum computers. Recently, there has been great interest in designing quantum logic gates by using the blockade effect of Rydberg atoms. The fidelity and operation speed of these gates, however, are fundamentally limited by an intrinsic blockade error. Here we propose a type of quantum gate, which is based on the Rydberg blockade effect, yet free from any blockade error. In contrast to the "blocking" method in previous schemes, we use the Rydberg energy shift to realize a rational generalized Rabi frequency so that a π phase for one input state of the gate emerges. This leads to an accurate Rydberg quantum logic gate that can operate on a 0.1 -μ s time scale or faster because it works by a Rabi frequency which is comparable to the blockade shift.

  16. Angiotensin II blockade: a strategy to slow ageing by protecting mitochondria? (United States)

    de Cavanagh, Elena M V; Inserra, Felipe; Ferder, León


    Protein and lipid oxidation-mainly by mitochondrial reactive oxygen species (mtROS)-was proposed as a crucial determinant of health and lifespan. Angiotensin II (Ang II) enhances ROS production by activating NAD(P)H oxidase and uncoupling endothelial nitric oxide synthase (NOS). Ang II also stimulates mtROS production, which depresses mitochondrial energy metabolism. In rodents, renin-angiotensin system blockade (RAS blockade) increases survival and prevents age-associated changes. RAS blockade reduces mtROS and enhances mitochondrial content and function. This suggests that Ang II contributes to the ageing process by prompting mitochondrial dysfunction. Since Ang II is a pleiotropic peptide, the age-protecting effects of RAS blockade are expected to involve a variety of other mechanisms. Caloric restriction (CR)-an age-retarding intervention in humans and animals-and RAS blockade display a number of converging effects, i.e. they delay the manifestations of hypertension, diabetes, nephropathy, cardiovascular disease, and cancer; increase body temperature; reduce body weight, plasma glucose, insulin, and insulin-like growth factor-1; ameliorate insulin sensitivity; lower protein, lipid, and DNA oxidation, and mitochondrial H(2)O(2) production; and increase uncoupling protein-2 and sirtuin expression. A number of these overlapping effects involve changes in mitochondrial function. In CR, peroxisome proliferator-activated receptors (PPARs) seem to contribute to age-retardation partly by regulating mitochondrial function. RAS inhibition up-regulates PPARs; therefore, it is feasible that PPAR modulation is pivotal for mitochondrial protection by RAS blockade during rodent ageing. Other potential mechanisms that may underlie RAS blockade's mitochondrial benefits are TGF-β down-regulation and up-regulation of Klotho and sirtuins. In conclusion, the available data suggest that RAS blockade deserves further research efforts to establish its role as a potential tool to

  17. Chronic blockade of angiotensin II action prevents glomerulosclerosis, but induces graft vasculopathy in experimental kidney transplantation

    NARCIS (Netherlands)

    Smit-van Oosten, A; Navis, G; Stegeman, CA; Joles, JA; Klok, PA; Kuipers, F; Tiebosch, ATMG; van Goor, H

    Long-term renin-angiotensin system blockade is beneficial in a variety of renal diseases, This study examines the long-term (34 weeks) effects of the angiotensin-converting enzyme inhibitor lisinopril and the angiotensin II receptor type I blocker L158,809 in the Fisher to Lewis rat model of chronic

  18. Does renin-angiotensin system blockade have a role in preventing diabetic retinopathy? A clinical review

    DEFF Research Database (Denmark)

    Sjølie, A K; Dodson, P; Hobbs, F R R


    been identified in the eye and found to be upregulated in retinopathy. This has led to specific interest in the role of RAS blockade in retinopathy prevention. The recent DIRECT programme assessed use of the angiotensin receptor blocker (ARB) candesartan in type 1 and type 2 diabetes. Although...

  19. Opioid Facilitation of β-Adrenergic Blockade: A New Pharmacological Condition? (United States)

    Vamecq, Joseph; Mention-Mulliez, Karine; Leclerc, Francis; Dobbelaere, Dries


    Recently, propranolol was suggested to prevent hyperlactatemia in a child with hypovolemic shock through β-adrenergic blockade. Though it is a known inhibitor of glycolysis, propranolol, outside this observation, has never been reported to fully protect against lactate overproduction. On the other hand, literature evidence exists for a cross-talk between β-adrenergic receptors (protein targets of propranolol) and δ-opioid receptor. In this literature context, it is hypothesized here that anti-diarrheic racecadotril (a pro-drug of thiorphan, an inhibitor of enkephalinases), which, in the cited observation, was co-administered with propranolol, might have facilitated the β-blocker-driven inhibition of glycolysis and resulting lactate production. The opioid-facilitated β-adrenergic blockade would be essentially additivity or even synergism putatively existing between antagonism of β-adrenergic receptors and agonism of δ-opioid receptor in lowering cellular cAMP and dependent functions.

  20. Opioid Facilitation of β-Adrenergic Blockade: A New Pharmacological Condition?

    Directory of Open Access Journals (Sweden)

    Joseph Vamecq


    Full Text Available Recently, propranolol was suggested to prevent hyperlactatemia in a child with hypovolemic shock through β-adrenergic blockade. Though it is a known inhibitor of glycolysis, propranolol, outside this observation, has never been reported to fully protect against lactate overproduction. On the other hand, literature evidence exists for a cross-talk between β-adrenergic receptors (protein targets of propranolol and δ-opioid receptor. In this literature context, it is hypothesized here that anti-diarrheic racecadotril (a pro-drug of thiorphan, an inhibitor of enkephalinases, which, in the cited observation, was co-administered with propranolol, might have facilitated the β-blocker-driven inhibition of glycolysis and resulting lactate production. The opioid-facilitated β-adrenergic blockade would be essentially additivity or even synergism putatively existing between antagonism of β-adrenergic receptors and agonism of δ-opioid receptor in lowering cellular cAMP and dependent functions.

  1. In-vitro blockade of the CD4 receptor co-signal in antigen-specific T-cell stimulation cultures induces the outgrowth of potent CD4 independent T-cell effectors. (United States)

    Vatter, Sarah; Schmid, Maximilian; Gebhard, Claudia; Mirbeth, Carina; Klobuch, Sebastian; Rehli, Michael; Herr, Wolfgang; Thomas, Simone


    T-cell receptor (TCR) redirected T cells are promising tools for adoptive cancer immunotherapy. Since not only CD8 but also CD4 T cells are key players for efficient antitumor responses, the targeted redirection of both subsets with the same antigen-specific TCR comes more and more into focus. Although rapidly evolving technologies enable the reliable genetic re-programming of T cells, the limited availability of TCRs that induce T-cell activation in both T-cell subsets without CD4/CD8 co-receptor contribution hampers the broad application of this approach. We developed a novel stimulation approach, which drives the activation and proliferation of CD4 T-cell populations capable of inducing effector functions in a CD4-independent manner. Naive-enriched CD4 T cells were stimulated against dendritic cells (DC) expressing allogeneic HLA-DP antigens upon RNA transfection and CD4/HLA interactions were blocked by the addition of CD4 binding antibody. Evolving CD4 T-cell populations were specifically activated independent of the CD4 co-signal and induced strong TCR-mediated IFN-γ secretion as well as cytolysis upon recognition of leukemia cells expressing HLA-DP antigen. Our novel stimulation approach may facilitate the generation of CD4 T cells as source for co-receptor independent TCRs for future immunotherapies. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Axillary brachial plexus blockade in moyamoya disease?

    Directory of Open Access Journals (Sweden)

    Saban Yalcin


    Full Text Available Moyamoya disease is characterized by steno-occlusive changes of the intracranial internal carotid arteries. Cerebral blood flow and metabolism are strictly impaired. The goal in perioperative anaesthetic management is to preserve the stability between oxygen supply and demand in the brain. Peripheral nerve blockade allows excellent neurological status monitoring and maintains haemodynamic stability which is very important in this patient group. Herein, we present an axillary brachial plexus blockade in a moyamoya patient operated for radius fracture.

  3. Association of the pattern of use of perioperative β-blockade and postoperative mortality. (United States)

    Wallace, Arthur W; Au, Selwyn; Cason, Brian A


    The 1996 atenolol study provided evidence that perioperative β-adrenergic receptor blockade (β-blockade) reduced postsurgical mortality. In 1998, the indications for perioperative β-blockade were codified as the Perioperative Cardiac Risk Reduction protocol and implemented at the San Francisco Veterans Administration Medical Center, San Francisco, California. The present study analyzed the association of the pattern of use of perioperative β-blockade with perioperative mortality since introduction of the Perioperative Cardiac Risk Reduction protocol. Epidemiologic analysis of the operations undertaken since 1996 at the San Francisco Veterans Administration Medical Center was performed. The pattern of use of perioperative β-blockade was divided into four groups: None, Addition, Withdrawal, and Continuous. Logistic regression, survival analysis, and propensity analysis were performed. A total of 38,779 operations were performed between 1996 and 2008. In patients meeting Perioperative Cardiac Risk Reduction indications for perioperative β-blockade, Addition is associated with a reduction in 30-day (odds ratio [OR], 0.52; 95% confidence interval [CI], 0.33 to 0.83; P = 0.006) and 1-yr mortality (OR, 0.64; 95%, CI 0.51 to 0.79; P < 0.0001). Continuous is associated with a reduction in 30-day (OR, 0.68; 95% CI, 0.47 to 0.98; P = 0.04) and 1-yr mortality (OR, 0.82; 95% CI, 0.67 to 1.0; P = 0.05). Withdrawal is associated with an increase in 30-day (OR 3.93, 95% CI, 2.57 to 6.01; P less than 0.0001) and 1-yr mortality (OR, 1.96; 95% CI, 1.49 to 2.58; P < 0.0001). Perioperative β-blockade administered according to the Perioperative Cardiac Risk Reduction protocol is associated with a reduction in 30-day and 1-yr mortality. Perioperative withdrawal of β-blockers is associated with increased mortality.

  4. Treatment of radiation nephropathy with ACE inhibitors and AII type-1 and type-2 receptor antagonists. (United States)

    Moulder, J E; Fish, B L; Cohen, E P


    Radiation nephropathy has emerged as a significant complication of bone marrow transplantation and radionuclide radiotherapy, and is a potential sequela of radiological terrorism and radiation accidents. In the early 1990's, it was demonstrated that experimental radiation nephropathy could be treated with a thiol-containing ACE inhibitor, captopril. Further studies have shown that enalapril (a non-thiol ACE inhibitor) is also effective in the treatment of experimental radiation nephropathy, as are both AII type-1 (AT(1)) and type-2 (AT(2)) receptor antagonists. ACE inhibitors and AII receptor antagonists are also effective in the mitigation (prevention) of radiation nephropathy. Other types of antihypertensive drugs are ineffective in mitigation, but brief use of a high-salt diet in the immediate post-irradiation period significantly decreases renal injury. There are differences between mitigation and treatment of radiation nephropathy that imply that different mechanisms are operating. First, a high-salt diet is effective in the mitigation of radiation nephropathy, but deleterious on the treatment of established disease. Second, AT(1) blockade is more effective than ACE inhibition for mitigation of radiation nephropathy, but equally effective for treatment. Third, the efficacy of AT(1) blockade and ACE inhibition is highly dependent on drug dose in mitigation of radiation nephropathy, but not so in treatment. Finally, while AT(2) blockade augments the benefit of AT(1) blockade in mitigation of radiation nephropathy, it does not do so in treatment. We hypothesize that while mitigation of radiation nephropathy works by suppression of the renin-angiotensin system, treatment of established radiation nephropathy requires blood pressure control in addition to (or possibly instead of) suppression of the renin-angiotensin system.

  5. Sodium restriction potentiates the renoprotective effects of combined vitamin D receptor activation and angiotensin-converting enzyme inhibition in established proteinuric nephropathy

    NARCIS (Netherlands)

    Mirkovic, Katarina; Frenay, Anne-Roos S; van den Born, Jacob; van Goor, Harry; Navis, Gerjan; de Borst, Martin H


    BACKGROUND: Renin-angiotensin-aldosterone system (RAAS) blockade provides renoprotective effects in chronic kidney disease (CKD); yet progressive renal function loss remains common. Dietary sodium restriction potentiates the renoprotective effects of RAAS blockade. Vitamin D receptor activator

  6. Role of hypocretin/orexin receptor blockade on drug-taking and ultrasonic vocalizations (USVs) associated with low-effort self-administration of cathinone-derived 3,4-methylenedioxypyrovalerone (MDPV) in rats. (United States)

    Simmons, Steven J; Martorana, Rose; Philogene-Khalid, Helene; Tran, Fionya H; Gentile, Taylor A; Xu, Xinyan; Su, Shu; Rawls, Scott M; Muschamp, John W


    Synthetic psychostimulant abuse, including cathinone-derived 3,4-methylenedioxypyrovalerone (MDPV), continues to increase in many countries. Similar to cocaine but with greater potency, MDPV elicits a transient sympathomimetic response by blocking cellular uptake of dopamine (DA) and norepinephrine (NE)-administration in some users is reported as euphoria-inducing much like cocaine and amphetamine. Pharmacological agents that disrupt excitatory transmission onto midbrain DA-producing neurons, including hypothalamic hypocretin/orexin (hcrt/ox) receptor antagonists, present attractive targets to aide abstinence maintenance by reducing psychostimulant-associated reward and reinforcement. The present study sought to assess the degree to which suvorexant, a dual hcrt/ox receptor antagonist, influences drug-taking as well as ultrasonic vocalizations (USVs) associated with MDPV self-administration. Rats were trained to self-administer MDPV (~0.03 mg/kg/inf, 3-s) for 14 days under a fixed-ratio 1 schedule of reinforcement, and effects of suvorexant (0, 3, 10, 30 mg/kg, i.p.) on drug-taking was assessed. USVs were recorded during a 30-min pre-lever period as well as during 2-h of MDPV self-administration. We observed that suvorexant modestly suppressed the number of MDPV infusions earned. Notably, we observed that suvorexant reduced 50-kHz USVs associated with pre- and post-lever time-points but did not noticeably alter call type profiles. Upon comparison of the two measures, we observed trending positive associations between suvorexant-induced changes in drug-taking and 50-kHz USVs. Results from this exploratory study provide support for the following: (1) studying how suvorexant may provide benefit to humans with stimulant use disorders, (2) identifying a potential role for orexin transmission in cathinone abuse, and (3) further interrogating the potential utility of rat USVs to predict drug consumption in preclinical models of substance use disorders.

  7. Clinical Evidence for the Cardiovascular Benefits of Angiotensin Receptor Blockers

    Directory of Open Access Journals (Sweden)

    Georg Nickenig


    Full Text Available Targeting the renin-angiotensin-aldosterone system (RAAS, specifically the effector peptide angiotensin II (Ang II, represents a major opportunity for slowing the progression of cardiovascular disease (CVD and, in turn, reducing the risk of morbidity and mortality. Inhibition of angiotensin-converting enzyme (ACE and selective blockade of Ang II AT1 receptors are two approaches through which the pathophysiological effects of Ang II can be targeted. Numerous clinical studies have established the benefits of ACE inhibitors (ACE-Is in lessening the morbidity and mortality burden of CVD. There are, however, tolerability concerns associated with ACE-Is, such as angioedema and dry cough. By blocking Ang II at the AT1 receptor lever, Ang II receptor blockers (ARBs provide a more specific and complete blockade of the deleterious effects of Ang II and tend to have more favourable tolerability. A number of clinical trials have shown that ARBs are not only associated with positive outcomes across the CVD continuum but may also have a role in the prevention or delay of diabetes (a major cardiovascular risk factor. Ongoing trials are aiming to define the place of such agents in lessening morbidity and mortality from CVD.

  8. Clinical Evidence for the Cardiovascular Benefits of Angiotensin Receptor Blockers

    Directory of Open Access Journals (Sweden)

    Georg Nickenig


    Full Text Available Targeting the renin-angiotensin-aldosterone system (RAAS, specifically the effector peptide angiotensin II (Ang II, represents a major opportunity for slowing the progression of cardiovascular disease (CVD and, in turn, reducing the risk of morbidity and mortality. Inhibition of angiotensin-converting enzyme (ACE and selective blockade of Ang II AT1 receptors are two approaches through which the pathophysiological effects of Ang II can be targeted. Numerous clinical studies have established the benefits of ACE inhibitors P, (ACE-Is in lessening the morbidity and mortality burden of CVD. There are, however, tolerability concerns associated with ACE-Is, such as angioedema and dry cough. By blocking Ang II at the AT1 receptor level, Ang II receptor blockers (ARBs provide a more specific and complete blockade of the deleterious effects of Ang II and tend to have more favourable tolerability. A number of clinical trials have shown that ARBs are not only associated with positive outcomes across the CVD continuum but may also have a role in the prevention or delay of diabetes (a major cardiovascular risk factor. Ongoing trials are aiming to define the place of such agents in lessening morbidity and mortality from CVD.

  9. Pancreatic digestive enzyme blockade in the small intestine prevents insulin resistance in hemorrhagic shock. (United States)

    DeLano, Frank A; Schmid-Schönbein, Geert W


    Hemorrhagic shock is associated with metabolic defects, including hyperglycemia and insulin resistance, but the mechanisms are unknown. We recently demonstrated that reduction of the extracellular domain of the insulin receptor by degrading proteases may lead to a reduced ability to maintain normal plasma glucose values. In shock, transfer of digestive enzymes from the lumen of the intestine into the systemic circulation after breakdown of the intestinal mucosal barrier causes inflammation and organ dysfunction. Suppression of the digestive enzymes in the lumen of the intestine with protease inhibitors is effective in reducing the level of the inflammatory reactions. To determine the degree to which blockade of digestive enzymes affects insulin resistance in shock, rats were exposed to acute hemorrhagic shock (mean arterial pressure of 30 mmHg for 2 h) at which time all shed blood volume was returned. Digestive proteases in the intestine were blocked with a serine protease inhibitor (tranexamic acid in polyethylene glycol and physiological electrolyte solution), and the density of the insulin receptor was measured with immunohistochemistry in the mesentery microcirculation. The untreated rat without enzyme blockade had significantly attenuated levels of insulin receptor density as compared with control and treated rats. Blockade of the digestive proteases after 60 min of hypotension in the lumen of the small intestine led to a lesser decrease in insulin receptor density compared with controls without protease blockade. Glucose tolerance test indicates a significant increase in plasma glucose levels 2 h after hemorrhagic shock, which are reduced to control values in the presence of protease inhibition in the lumen of the intestine. The transient reduction of the plasma glucose levels after an insulin bolus is significantly attenuated after shock but is restored when digestive enzymes in the lumen of the intestine are blocked. These results suggest that in

  10. Localized CD47 blockade enhances immunotherapy for murine melanoma. (United States)

    Ingram, Jessica R; Blomberg, Olga S; Sockolosky, Jonathan T; Ali, Lestat; Schmidt, Florian I; Pishesha, Novalia; Espinosa, Camilo; Dougan, Stephanie K; Garcia, K Christopher; Ploegh, Hidde L; Dougan, Michael


    CD47 is an antiphagocytic ligand broadly expressed on normal and malignant tissues that delivers an inhibitory signal through the receptor signal regulatory protein alpha (SIRPα). Inhibitors of the CD47-SIRPα interaction improve antitumor antibody responses by enhancing antibody-dependent cellular phagocytosis (ADCP) in xenograft models. Endogenous expression of CD47 on a variety of cell types, including erythrocytes, creates a formidable antigen sink that may limit the efficacy of CD47-targeting therapies. We generated a nanobody, A4, that blocks the CD47-SIRPα interaction. A4 synergizes with anti-PD-L1, but not anti-CTLA4, therapy in the syngeneic B16F10 melanoma model. Neither increased dosing nor half-life extension by fusion of A4 to IgG2a Fc (A4Fc) overcame the issue of an antigen sink or, in the case of A4Fc, systemic toxicity. Generation of a B16F10 cell line that secretes the A4 nanobody showed that an enhanced response to several immune therapies requires near-complete blockade of CD47 in the tumor microenvironment. Thus, strategies to localize CD47 blockade to tumors may be particularly valuable for immune therapy.

  11. Concomitant manipulation of murine NMDA- and AMPA-receptors to produce pro-cognitive drug effects in mice. (United States)

    Vignisse, Julie; Steinbusch, Harry W M; Grigoriev, Vladimir; Bolkunov, Alexei; Proshin, Alexey; Bettendorff, Lucien; Bachurin, Sergey; Strekalova, Tatyana


    Bifunctional drug therapy targeting distinct receptor signalling systems can generate increased efficacy at lower concentrations compared to monofunctional therapy. Non-competitive blockade of the NMDA receptors or the potentiation of AMPA receptors is well documented to result in memory enhancement. Here, we compared the efficacy of the low-affinity NMDA receptor blocker memantine or the positive modulator of AMPA receptor QXX (in C57BL/6J at 1 or 5mg/kg, ip) with new derivatives of isothiourea (0.5-1 mg/kg, ip) that have bifunctional efficacy. Low-affinity NMDA blockade by these derivatives was achieved by introducing greater flexibility into the molecule, and AMPA receptor stimulation was produced by a sulfamide-containing derivative of isothiourea. Contextual learning was examined in a step-down avoidance task and extinction of contextual memory was studied in a fear-conditioning paradigm. Memantine enhanced contextual learning while QXX facilitated memory extinction; both drugs were effective at 5 mg/kg. The new derivative IPAC-5 elevated memory scores in both tasks at the dose 0.5 mg/kg and exhibited the lowest IC₅₀ values of NMDA receptor blockade and highest potency of AMPA receptor stimulation. Thus, among the new drugs tested, IPAC-5 replicated the properties of memantine and QXX in one administration with increased potency. Our data suggest that a concomitant manipulation of NMDA- and AMPA-receptors results in pro-cognitive effects and supports the concept bifunctional drug therapy as a promising strategy to replace monofunctional therapies with greater efficacy and improved compliance. Copyright © 2013 Elsevier B.V. and ECNP. All rights reserved.

  12. A Phase I-II Study of Combined Blockade of the ErbB Receptor Network with Trastuzumab and Gefitinib in Patients with HER2 (ErbB2)-Overexpressing Metastatic Breast Cancer (United States)

    Arteaga, Carlos L.; O’Neill, Anne; Moulder, Stacy L.; Pins, Michael; Sparano, Joseph A.; Sledge, George W.; Davidson, Nancy E.


    Purpose To determine the safety, and efficacy of the epidermal growth factor receptor tyrosine kinase inhibitor gefitinib in combination with trastuzumab in patients with metastatic HER2-positive metastatic breast cancer. Experimental Design Patients with HER2-overexpressing breast cancer were treated with trastuzumab 2 mg/kg/week and gefitinib 250 to 500 mg/day. The primary end point of the study was to increase the proportion progression-free from 50% to 65% at 6 months in chemotherapy-naive patients and from 50% to 70% at 3 months in patients previously treated with chemotherapy in the metastatic setting. Results In the phase I study, all patients treated with gefitinib 500 mg/day developed grade 3 diarrhea. The phase II study was conducted using trastuzumab and gefitinib 250 mg/day. One patient achieved a complete response, 2 had a partial response, and 6 had stable disease for an overall response rate of 9% and a clinical benefit rate of 28% (9 of 32). Median time to progression (TTP) was 3 months (95% confidence interval, 2.3-4.1) in patients with no prior systemic therapy in the metastatic setting (n = 23). In patients treated with prior systemic therapy (n = 9), the median TTP of 5.3 months (95% confidence interval, 2.8-8.1). Overall median survival was 27 months. TTP was similar in EGFR-positive compared with EGFR-negative patients. Conclusions Gefitinib 250 mg/day was the maximal dose that can be safely administered with weekly trastuzumab. Interim analysis of the efficacy suggested that the combination was unlikely to result in clinical benefit compared with trastuzumab alone. These results do not support the use of this combination in patients with HER2-positive breast cancer. PMID:18829509

  13. Effect of desiccating environmental stress versus systemic muscarinic AChR blockade on dry eye immunopathogenesis. (United States)

    Chen, Yihe; Chauhan, Sunil K; Lee, Hyun Soo; Stevenson, William; Schaumburg, Chris S; Sadrai, Zahra; Saban, Daniel R; Kodati, Shilpa; Stern, Michael E; Dana, Reza


    A majority of experimental data on dry eye disease (DED) immunopathogenesis have been derived from a murine model of DED that combines desiccating environmental stress with systemic muscarinic acetylcholine receptor (mAChR) inhibition. However, to our knowledge the effects of pharmacologic mAChR blockade on the pathogenesis of experimental DED have not been evaluated systemically. The purpose of our study was to investigate the differential effects of desiccating environmental stress and mAChR inhibition on the pathogenesis of DED. DED was induced in female C57BL/6 mice by exposure to a desiccating environment in the controlled-environment chamber or to systemic scopolamine, or by performing extraorbital lacrimal gland excision. Clinical disease was assessed using corneal fluorescein staining (CFS) and the cotton thread test (CTT). Corneal CD11b(+) and conjunctival CD3(+) T-cell infiltration were evaluated by flow cytometry. T-cells from draining cervical lymph nodes (CLN) and distant inguinal lymph nodes (ILN) were analyzed for Th1, Th2, Th17, and Treg responses by flow cytometry and ELISA. Desiccating environmental stress and systemic mAChR blockade induced similar clinical signs of DED. However, desiccating environmental stress imparted higher conjunctival CD3(+) T-cell infiltration, and greater Th17-cell activity and Treg dysfunction than mAChR blockade, while mAChR blockade decreased tear secretion to a greater extent than desiccating environmental stress. Systemic mAChR blockade attenuated Th17 activity and enhanced Th2 and Treg responses without affecting Th1 activity. In vivo inhibition of mAChRs variably affects CD4(+) T-cell subsets, and desiccating environmental stress and systemic mAChR blockade induce DED through different primary pathogenic mechanisms.

  14. receptores

    Directory of Open Access Journals (Sweden)

    Salete Regina Daronco Benetti


    Full Text Available Se trata de un estudio etnográfico, que tuvo lo objetivo de interpretar el sistema de conocimiento y del significado atribuidos a la sangre referente a la transfusión sanguínea por los donadores y receptores de un banco de sangre. Para la colecta de las informaciones se observaron los participantes y la entrevista etnográfica se realizó el análisis de dominio, taxonómicos y temáticos. Los dominios culturales fueron: la sangre es vida: fuente de vida y alimento valioso; creencias religiosas: fuentes simbólicas de apoyos; donación sanguínea: un gesto colaborador que exige cuidarse, gratifica y trae felicidad; donación sanguínea: fuente simbólica de inseguridad; estar enfermo es una condición para realizar transfusión sanguínea; transfusión sanguínea: esperanza de vida; Creencias populares: transfusión sanguínea como riesgo para la salud; donadores de sangre: personas benditas; donar y recibir sangre: como significado de felicidad. Temática: “líquido precioso que origina, sostiene, modifica la vida, provoca miedo e inseguridad”.

  15. Immune Checkpoint Blockade in Cancer Therapy

    National Research Council Canada - National Science Library

    Postow, Michael A; Callahan, Margaret K; Wolchok, Jedd D


    ... agents that target these pathways. Treatment with both CTLA-4 and PD-1/PD-L1 blockade is associated with a unique pattern of adverse events called immune-related adverse events, and occasionally, unusual kinetics of tumor response are seen...

  16. [Ultrasound-guided peripheral nerve blockade]. (United States)

    Schwemmer, Ulrich; Markus, Christian K; Brederlau, Jörg; Roewer, Norbert


    Without miniaturization resulting in affordable hand-held ultrasound systems, ultrasound-guided regional anaesthesia would not be practicable. Nowadays facilitation of nerve blockade by means of ultrasound is achievable even in remote locations. Non-traumatic technique, visualisation of nerves, surrounding structures and the ability to assess the spread of the injected local anaesthetic combined with a high and predictable success rate are the major advantages when ultrasound is used in regional anaesthetic practise. After a short recapitulation of physical principles related to ultrasound this article focuses on the specific features related to ultrasound-guided identification and blockade of peripheral nerves. Technical pitfalls and their implications for a successful nerve block are put into perspective. Ultrasound can be used to facilitate blockade of the upper and lower extremity. The advantages and limitations of the technique when applied to the classical approaches for blockade of the brachial plexus and the femoral and ischiadic nerve are discussed. Ultrasound-guided regional anaesthesia is a valuable tool to improve safety, success rate and patient comfort in daily anaesthetic practise.

  17. ACE insertion/deletion polymorphism (rs1799752) modifies the renoprotective effect of renin-angiotensin system blockade in patients with IgA nephropathy. (United States)

    Teranishi, Junya; Yamamoto, Ryohei; Nagasawa, Yasuyuki; Shoji, Tatsuya; Iwatani, Hirotsugu; Okada, Noriyuki; Moriyama, Toshiki; Yamauchi, Atsushi; Tsubakihara, Yoshiharu; Imai, Enyu; Rakugi, Hiromi; Isaka, Yoshitaka


    Little is known about genetic predictors that modify the renoprotective effect of renin-angiotensin system (RAS) blockade in IgA nephropathy (IgAN). The present multicenter retrospective observational study examined effect modification between RAS blockade and three RAS-related gene polymorphisms in 237 IgAN patients, including ACE I/D (rs1799752), AT1R A1166C (rs5186) and AGT T704C (rs699). During 9.9 ± 4.2 years of observation, 63 patients progressed to a 50% increase in serum creatinine level. Only ACE I/D predicted the outcome (ACE DD vs ID/II, hazard ratio 1.86 (95% confidence interval 1.03, 3.33)) and modified the renoprotective effect of RAS blockade (p for interaction between ACE DD and RAS blockade = 0.087). RAS blockade suppressed progression in ACE DD patients but not in ID/II patients (ACE ID/II with RAS blockade as a reference; ID/II without RAS blockade 1.45 (0.72, 2.92); DD without RAS blockade 3.06 (1.39, 6.73); DD with RAS blockade 1.51 (0.54, 4.19)), which was ascertained in a model with the outcome of slope of estimated glomerular filtration rate (p = 0.045 for interaction). ACE I/D predicted the IgAN progression and the renoprotective effect of RAS blockade in IgAN patients whereas neither AT1R A1166C nor AGT T704C did. © The Author(s) 2014.

  18. Blockade of the angiotensin system improves mental health domain of quality of life: A meta-analysis of randomized clinical trials. (United States)

    Brownstein, Daniel J; Salagre, Estela; Köhler, Cristiano; Stubbs, Brendon; Vian, João; Pereira, Ciria; Chavarria, Victor; Karmakar, Chandan; Turner, Alyna; Quevedo, João; Carvalho, André F; Berk, Michael; Fernandes, Brisa S


    It is unclear whether blockade of the angiotensin system has effects on mental health. Our objective was to determine the impact of angiotensin converting enzyme inhibitors and angiotensin II type 1 receptor (AT1R) blockers on mental health domain of quality of life. Meta-analysis of published literature. PubMed and databases. The last search was conducted in January 2017. Randomized controlled trials comparing any angiotensin converting enzyme inhibitor or AT1R blocker versus placebo or non-angiotensin converting enzyme inhibitor or non-AT1R blocker were selected. Study participants were adults without any major physical symptoms. We adhered to meta-analysis reporting methods as per PRISMA and the Cochrane Collaboration. Eleven studies were included in the analysis. When compared with placebo or other antihypertensive medications, AT1R blockers and angiotensin converting enzyme inhibitors were associated with improved overall quality of life (standard mean difference = 0.11, 95% confidence interval = [0.08, 0.14], p quality of life. Mental health quality of life was a secondary outcome in the included studies. Research specifically designed to analyse the usefulness of drugs that block the angiotensin system is necessary to properly evaluate this novel psychiatric target.

  19. Changes in gene expression following androgen receptor blockade ...

    Indian Academy of Sciences (India)

    Madhu urs

    phosphatase-conjugated anti-DIG Fab fragments (diluted 1: 1000 in blocking solution) was applied to each section and incubated at room temperature for 2 h. Excess antibody was washed with PBS and the sections were exposed to NBT/. BCIP substrate until specific staining was observed with minimum background.

  20. Opioid Receptors Blockade Modulates Apoptosis in a Rat Model of ...

    African Journals Online (AJOL)

    Introduction. Cirrhosis is a common consequence of chronic liver inflammation characterized by replacement of liver tissue by fibrous scar and regenerative tissue, leading to a progressive loss of liver function.[1] Cirrhosis is known to be associated with various cardiovascular abnormalities, including increased.

  1. Changes in gene expression following androgen receptor blockade ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Biosciences; Volume 33; Issue 2 ... Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560 012, India; Chromatin Biology Lab, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 064, India ...

  2. Opioid receptors blockade modulates apoptosis in a rat model of ...

    African Journals Online (AJOL)

    Background: Cirrhosis is a common consequence of chronic liver inflammation is known to be associated with various manifestation of cardiovascular dysfunction, which has been introduced as a cirrhotic cardiomyopathy. Some possible pathogenic mechanisms has been reported and still more details should be explored.

  3. Neuromuscular blockade during laparoscopic ventral herniotomy

    DEFF Research Database (Denmark)

    Medici, Roar; Madsen, Matias V; Asadzadeh, Sami


    's rating of surgical conditions during suturing, duration of surgery and duration of the suturing of the hernia. CONCLUSION: This randomised cross-over study investigated a potential effect on the surgical workspace in laparoscopic ventral herniotomy using deep NMB compared with no NMB. The study may......INTRODUCTION: Laparoscopic herniotomy is the preferred technique for some ventral hernias. Several factors may influence the surgical conditions, one being the depth of neuromuscular blockade (NMB) applied. We hypothesised that deep neuromuscular blockade defined as a post-tetanic count below eight...... would provide a better surgical workspace. METHODS: This was an investigator-initiated, assessor- and patient-blinded randomised cross-over study. A total of 34 patients with planned laparoscopic umbilical, incisional and linea alba herniotomy were studied. Patients would be randomised to receive deep...

  4. Efficient Multiparticle Entanglement via Asymmetric Rydberg Blockade

    DEFF Research Database (Denmark)

    Saffman, Mark; Mølmer, Klaus


    We present an efficient method for producing N particle entangled states using Rydberg blockade interactions. Optical excitation of Rydberg states that interact weakly, yet have a strong coupling to a second control state is used to achieve state dependent qubit rotations in small ensembles. On t....... On the basis of quantitative calculations, we predict that an entangled quantum superposition state of eight atoms can be produced with a fidelity of 84% in cold Rb atoms.......We present an efficient method for producing N particle entangled states using Rydberg blockade interactions. Optical excitation of Rydberg states that interact weakly, yet have a strong coupling to a second control state is used to achieve state dependent qubit rotations in small ensembles...

  5. Neuromuscular blockade during laparoscopic ventral herniotomy

    DEFF Research Database (Denmark)

    Medici, Roar; Madsen, Matias V; Asadzadeh, Sami


    INTRODUCTION: Laparoscopic herniotomy is the preferred technique for some ventral hernias. Several factors may influence the surgical conditions, one being the depth of neuromuscular blockade (NMB) applied. We hypothesised that deep neuromuscular blockade defined as a post-tetanic count below eight......'s rating of surgical conditions during suturing, duration of surgery and duration of the suturing of the hernia. CONCLUSION: This randomised cross-over study investigated a potential effect on the surgical workspace in laparoscopic ventral herniotomy using deep NMB compared with no NMB. The study may...... provide knowledge relevant to other laparoscopic techniques. FUNDING: The study is funded by a research grant from the Investigator Initiated Studies Program of Merck Sharp & Dohme Corp. TRIAL REGISTRATION: NCT02247466....

  6. hERG Blockade by Iboga Alkaloids. (United States)

    Alper, Kenneth; Bai, Rong; Liu, Nian; Fowler, Steven J; Huang, Xi-Ping; Priori, Silvia G; Ruan, Yanfei


    The iboga alkaloids are a class of naturally occurring and synthetic compounds, some of which modify drug self-administration and withdrawal in humans and preclinical models. Ibogaine, the prototypic iboga alkaloid that is utilized clinically to treat addictions, has been associated with QT prolongation, torsades de pointes and fatalities. hERG blockade as IKr was measured using the whole-cell patch clamp technique in HEK 293 cells. This yielded the following IC50 values: ibogaine manufactured by semisynthesis via voacangine (4.09 ± 0.69 µM) or by extraction from T. iboga (3.53 ± 0.16 µM); ibogaine's principal metabolite noribogaine (2.86 ± 0.68 µM); and voacangine (2.25 ± 0.34 µM). In contrast, the IC50 of 18-methoxycoronaridine, a product of rational synthesis and current focus of drug development was >50 µM. hERG blockade was voltage dependent for all of the compounds, consistent with low-affinity blockade. hERG channel binding affinities (K i) for the entire set of compounds, including 18-MC, ranged from 0.71 to 3.89 µM, suggesting that 18-MC binds to the hERG channel with affinity similar to the other compounds, but the interaction produces substantially less hERG blockade. In view of the extended half-life of noribogaine, these results may relate to observations of persistent QT prolongation and cardiac arrhythmia at delayed intervals of days following ibogaine ingestion. The apparent structure-activity relationships regarding positions of substitutions on the ibogamine skeleton suggest that the iboga alkaloids might provide an informative paradigm for investigation of the structural biology of the hERG channel.

  7. Efficient Grover search with Rydberg blockade


    Molmer, Klaus; Isenhower, Larry; Saffman, Mark


    We present efficient methods to implement the quantum computing Grover search algorithm using the Rydberg blockade interaction. We show that simple pi-pulse excitation sequences between ground and Rydberg excited states readily produce the key conditional phase shift and inversion-about-the mean unitary operations for the Grover search. Multi-qubit implementation schemes suitable for different properties of the atomic interactions are identifed and the error scaling of the protocols with syst...

  8. Immune checkpoint blockade in small cell lung cancer: is there a light at the end of the tunnel? (United States)

    Paglialunga, Luca; Salih, Zena; Ricciuti, Biagio; Califano, Raffaele


    Small cell lung cancer (SCLC) is a very aggressive disease, characterised by rapid growth, high response rates to both chemotherapy and radiotherapy and subsequent development of treatment resistance in the vast majority of patients. In the past 30 years, little progress has been made in systemic treatments and the established management paradigm of platinum-based chemotherapy has reached an efficacy plateau. Several clinical trials have investigated targeted therapies, without producing clinically significant benefits. Recently presented early phase clinical trials with immune checkpoint inhibitors (blockade of the cytotoxic T-lymphocyte antigen-4 (CTLA-4) and blockade of the programmed cell death-1 (PD-1) receptor) have shown promising results. In this review, we present the emerging evidence on immune checkpoint blockade for SCLC. PMID:27843619

  9. Smoldering myocarditis following immune checkpoint blockade. (United States)

    Norwood, Timothy G; Westbrook, Brian C; Johnson, Douglas B; Litovsky, Silvio H; Terry, Nina L; McKee, Svetlana B; Gertler, Alan S; Moslehi, Javid J; Conry, Robert M


    Severe myocarditis associated with electrical conduction abnormalities and occasionally heart failure has been well documented following treatment with immune checkpoint blockade with an estimated incidence of less than 1%. However, the incidence, early detection, and management of less severe immune-related myocarditis are unknown since most immunotherapy trials have not included routine cardiac monitoring. Herein, we provide the first description of subclinical or smoldering myocarditis with minimal signs and symptoms following immune checkpoint blockade with a single dose of ipilimumab and nivolumab. Our patient was diagnosed with immune checkpoint blockade-induced myocarditis based upon an acute rise in serum cardiac troponin I beginning 2 weeks after the initial dose of ipilimumab/nivolumab consistent with the reported median onset of clinical myocarditis at 17 days, as well as a lack of other causes despite extensive cardiac evaluation. The patient initially presented with intractable nausea with no known gastrointestinal etiology. High dose glucocorticoid therapy led to rapid resolution of nausea and a four-fold decrease in troponin I over 4 days. Serum troponin I spiked again following a steroid taper to 13 times the upper limit of normal with endomyocardial biopsy revealing collagen fibrosis and lymphocytic inflammation predominantly comprised of CD8+ T cells consistent with chronic smoldering myocarditis. Serum anti-striated muscle antibodies were also detected with no evidence of rhabdomyolysis. Serum cardiac troponin I levels as an indicator of ongoing myocyte damage gradually improved with chronic prednisone at 10 mg daily. Late addition of intravenous immunoglobulin was associated with rapid normalization of creatine kinase-myocardial band. This case demonstrates that subclinical, smoldering myocarditis may occur following immune checkpoint blockade, with evidence of both humoral and cell-mediated immunity responsive to corticosteroid therapy

  10. Angiotensin II blockade causes acute renal failure in eNOS-deficient mice

    Directory of Open Access Journals (Sweden)

    Jürgen Schnermann


    Full Text Available Compared with wild-type mice, adult endothelial nitric oxide synthase (eNOS knockout mice (eight months of age have increased blood pressure (BP (126±9 mmHg vs. 100±4 mmHg, and an increased renal vascular resistance (155±16 vs. 65±4 mmHg.min/ml. Renal vascular resistance responses to i.v. administration of noradrenaline were markedly enhanced in eNOS knockout mice. Glomerular filtration rate (GFR of anaesthetised eNOS -/- mice was 324±57 µl/min gKW, significantly lower than the GFR of 761±126 µl/min.gKW in wild-type mice. AT1-receptor blockade with i.v. candesartan (1—1.5 mg/kg reduced arterial blood pressure and renal vascular resistance, and increased renal blood flow (RBF to about the same extent in wild-type and eNOS -/- mice. Candesartan did not alter GFR in wild-type mice (761±126 vs. 720±95 µl/min.gKW, but caused a marked decrease in GFR in eNOS -/- mice (324.5±75.2 vs. 77±18 µl/min.gKW. A similar reduction in GFR of eNOS deficient mice was also caused by angiotensin-converting enzyme (ACE inhibition. Afferent arteriolar granularity, a measure of renal renin expression, was found to be reduced in eNOS -/- compared with wild-type mice. In chronically eNOS-deficient mice, angiotensin II (Ang II is critical for maintaining glomerular filtration pressure and GFR, presumably through its effect on efferent arteriolar tone.

  11. Blockade of the renin-angiotensin system improves cerebral microcirculatory perfusion in diabetic hypertensive rats. (United States)

    Estato, Vanessa; Obadia, Nathalie; Carvalho-Tavares, Juliana; Freitas, Felipe Santos; Reis, Patrícia; Castro-Faria Neto, Hugo; Lessa, Marcos Adriano; Tibiriçá, Eduardo


    We examined the functional and structural microcirculatory alterations in the brain, skeletal muscle and myocardium of non-diabetic spontaneously hypertensive rats (SHR) and diabetic SHR (D-SHR), as well as the effects of long-term treatment with the angiotensin AT1-receptor antagonist olmesartan and the angiotensin-converting enzyme inhibitor enalapril. Diabetes was experimentally induced by a combination of a high-fat diet with a single low dose of streptozotocin (35 mg/kg, intraperitoneal injection). D-SHR were orally administered with olmesartan (5 mg/kg/day), enalapril (10 mg/kg/day) or vehicle for 28 days, and compared with vehicle-treated non-diabetic SHR or normotensive non-diabetic Wistar-Kyoto rats. The cerebral and skeletal muscle functional capillary density of pentobarbital-anesthetized rats was assessed using intravital fluorescence videomicroscopy. Chronic treatment with olmesartan or enalapril significantly lowered blood pressure and reversed brain functional capillary rarefaction. Brain oxidative stress was reduced to non-diabetic control levels in animals treated with olmesartan or enalapril. Histochemical analysis of the structural capillary density showed that both olmesartan and enalapril increased the capillary-to-fiber ratio in skeletal muscle and the capillary-to-fiber volume density in the left ventricle. Olmesartan and enalapril also prevented collagen deposition and the increase in cardiomyocyte diameter in the left ventricle. Our results suggest that the association between hypertension and diabetes results in microvascular alterations in the brain, skeletal muscle and myocardium that can be prevented by chronic blockade of the renin-angiotensin system. Copyright © 2013 Elsevier Inc. All rights reserved.

  12. How does angiotensin AT2 receptor activation help neuronal differentiation and improve neuronal pathological situations? (United States)

    Guimond, Marie-Odile; Gallo-Payet, Nicole


    The angiotensin type 2 (AT2) receptor of angiotensin II has long been thought to be limited to few tissues, with the primary effect of counteracting the angiotensin type 1 (AT1) receptor. Functional studies in neuronal cells have demonstrated AT2 receptor capability to modulate neuronal excitability, neurite elongation, and neuronal migration, suggesting that it may be an important regulator of brain functions. The observation that the AT2 receptor was expressed in brain areas implicated in learning and memory led to the hypothesis that it may also be implicated in cognitive functions. However, linking signaling pathways to physiological effects has always proven challenging since information relative to its physiological functions has mainly emerged from indirect observations, either from the blockade of the AT1 receptor or through the use of transgenic animals. From a mechanistic standpoint, the main intracellular pathways linked to AT2 receptor stimulation include modulation of phosphorylation by activation of kinases and phosphatases or the production of nitric oxide and cGMP, some of which are associated with the Gi-coupling protein. The receptor can also interact with other receptors, either G protein-coupled such as bradykinin, or growth factor receptors such as nerve growth factor or platelet-derived growth factor receptors. More recently, new advances have also led to identification of various partner proteins, thus providing new insights into this receptor’s mechanism of action. This review summarizes the recent advances regarding the signaling pathways induced by the AT2 receptor in neuronal cells, and discussed the potential therapeutic relevance of central actions of this enigmatic receptor. In particular, we highlight the possibility that selective AT2 receptor activation by non-peptide and selective agonists could represent new pharmacological tools that may help to improve impaired cognitive performance in Alzheimer’s disease and other

  13. Angiotensin type 2 receptor (AT2R) and receptor Mas

    DEFF Research Database (Denmark)

    Villela, Daniel; Leonhardt, Julia; Patel, Neal


    The angiotensin type 2 receptor (AT2R) and the receptor Mas are components of the protective arms of the renin-angiotensin system (RAS), i.e. they both mediate tissue protective and regenerative actions. The spectrum of actions of these two receptors and their signalling mechanisms display striking...... the phenomenon of blockade of angiotensin-(1-7) [Ang-(1-7)] actions by AT2R antagonists and vice versa. Such mechanisms may comprise dimerization of the receptors or dimerization-independent mechanisms such as lack of specificity of the receptor ligands used in the experiments or involvement of the Ang-(1...

  14. Dopamine 5 receptor mediates Ang II type 1 receptor degradation via a ubiquitin-proteasome pathway in mice and human cells (United States)

    Li, Hewang; Armando, Ines; Yu, Peiying; Escano, Crisanto; Mueller, Susette C.; Asico, Laureano; Pascua, Annabelle; Lu, Quansheng; Wang, Xiaoyan; Villar, Van Anthony M.; Jones, John E.; Wang, Zheng; Periasamy, Ammasi; Lau, Yuen-Sum; Soares-da-Silva, Patricio; Creswell, Karen; Guillemette, Gaétan; Sibley, David R.; Eisner, Gilbert; Felder, Robin A.; Jose, Pedro A.


    Hypertension is a multigenic disorder in which abnormal counterregulation between dopamine and Ang II plays a role. Recent studies suggest that this counterregulation results, at least in part, from regulation of the expression of both the antihypertensive dopamine 5 receptor (D5R) and the prohypertensive Ang II type 1 receptor (AT1R). In this report, we investigated the in vivo and in vitro interaction between these GPCRs. Disruption of the gene encoding D5R in mice increased both blood pressure and AT1R protein expression, and the increase in blood pressure was reversed by AT1R blockade. Activation of D5R increased the degradation of glycosylated AT1R in proteasomes in HEK cells and human renal proximal tubule cells heterologously and endogenously expressing human AT1R and D5R. Confocal microscopy, Förster/fluorescence resonance energy transfer microscopy, and fluorescence lifetime imaging microscopy revealed that activation of D5R initiated ubiquitination of the glycosylated AT1R at the plasma membrane. The regulated degradation of AT1R via a ubiquitin/proteasome pathway by activation of D5R provides what we believe to be a novel mechanism whereby blood pressure can be regulated by the interaction of 2 counterregulatory GPCRs. Our results therefore suggest that treatments for hypertension might be optimized by designing compounds that can target the AT1R and the D5R. PMID:18464932

  15. SHP-1 phosphatase activity counteracts increased T cell receptor affinity

    National Research Council Canada - National Science Library

    Hebeisen, Michael; Baitsch, Lukas; Presotto, Danilo; Baumgaertner, Petra; Romero, Pedro; Michielin, Olivier; Speiser, Daniel E; Rufer, Nathalie


    .... Preferential expression of the inhibitory receptor programmed cell death-1 (PD-1) was limited to T cells with the highest TCR affinity, correlating with full functional recovery upon PD-1 ligand 1 (PD-L1) blockade...

  16. Neuraxial blockade for external cephalic version: Cost analysis. (United States)

    Yamasato, Kelly; Kaneshiro, Bliss; Salcedo, Jennifer


    Neuraxial blockade (epidural or spinal anesthesia/analgesia) with external cephalic version increases the external cephalic version success rate. Hospitals and insurers may affect access to neuraxial blockade for external cephalic version, but the costs to these institutions remain largely unstudied. The objective of this study was to perform a cost analysis of neuraxial blockade use during external cephalic version from hospital and insurance payer perspectives. Secondarily, we estimated the effect of neuraxial blockade on cesarean delivery rates. A decision-analysis model was developed using costs and probabilities occurring prenatally through the delivery hospital admission. Model inputs were derived from the literature, national databases, and local supply costs. Univariate and bivariate sensitivity analyses and Monte Carlo simulations were performed to assess model robustness. Neuraxial blockade was cost saving to both hospitals ($30 per delivery) and insurers ($539 per delivery) using baseline estimates. From both perspectives, however, the model was sensitive to multiple variables. Monte Carlo simulation indicated neuraxial blockade to be more costly in approximately 50% of scenarios. The model demonstrated that routine use of neuraxial blockade during external cephalic version, compared to no neuraxial blockade, prevented 17 cesarean deliveries for every 100 external cephalic versions attempted. Neuraxial blockade is associated with minimal hospital and insurer cost changes in the setting of external cephalic version, while reducing the cesarean delivery rate. © 2015 The Authors. Journal of Obstetrics and Gynaecology Research © 2015 Japan Society of Obstetrics and Gynecology.


    Bazhan, N M; Kulikova, E V; Makarova, E N; Yakovleva, T V; Kazantseva, A Yu


    Melanocortin (MC) system regulates food intake under the rest conditions. Stress inhibits food intake. It is not clear whether brain MC system is involved in stress-induced anorexia in mice. The aim of the work was to investigate the effect of pharmacological blockade and activation of brain MC receptors on food intake under stress. C57B1/6J male mice were subjected to ether stress (0.5 minute ether anesthesia) before the administration of saline solution or synthetic non-selective blocker (SHU9119) or agonist (Melanotan II) of MC receptors into the lateral brain ventricle. Food intake was pre-stimulated with 17 hours of fasting in all mice. Ether stress decreased food intake, increased the plasma corticosterone level and hypothalamic mRNA AgRP (natural MC receptor antagonist) level at 1 hour after the stress. Pharmacological blockade of the MC receptors weakened stress-induced anorexia and decreased mRNA AgRP level in the hypothalamus. Pharmacological stimulation of the MC receptors enhanced ether stress-induced anorexia and hypercortisolism. Thus, our data demonstrated that the central MC system was involved in the development of stress-induced anorexia in mice.

  18. The Role of Apelin on the Alleviative Effect of Angiotensin Receptor Blocker in Unilateral Ureteral Obstruction-Induced Renal Fibrosis

    Directory of Open Access Journals (Sweden)

    Masashi Nishida


    Full Text Available Background: Apelin is a selective endogenous ligand of the APJ receptor, which genetically has closest identity to the angiotensin II type 1 receptor (AT-1. The effects of the apelin/APJ system on renal fibrosis still remain unclear. Methods: We examined the effects of the apelin/APJ system on renal fibrosis during AT-1 blockade in a mouse unilateral ureteral obstruction (UUO model. Results: We obtained the following results: (1 At UUO day 7, mRNA expressions of apelin/APJ and phosphorylations of Akt/endothelial nitric oxide synthase (eNOS in the UUO kidney were increased compared to those in the nonobstructed kidney. (2 AT-1 blockade by the treatment with losartan resulted in a further increase of apelin mRNA as well as phosphorylations of Akt/eNOS proteins, and this was accompanied by alleviated renal interstitial fibrosis, decreased myofibroblast accumulation, and a decreased number of interstitial macrophages. (3 Blockade of the APJ receptor by the treatment with F13A during losartan administration completely abrogated the effects of losartan in the activation of the Akt/eNOS pathway and the amelioration of renal fibrosis. (4 Inhibition of NOS by the treatment with L-NAME also resulted in a further increase in renal fibrosis compared to the control group. Conclusion: These results suggest that increased nitric oxide production through the apelin/APJ/Akt/eNOS pathway may, at least in part, contribute to the alleviative effect of losartan in UUO-induced renal fibrosis.

  19. Checkpoint Blockade in Lung Cancer and Mesothelioma. (United States)

    Lievense, Lysanne A; Sterman, Daniel H; Cornelissen, Robin; Aerts, Joachim G


    In the last decade, immunotherapy has emerged as a new treatment modality in cancer. The most success has been achieved with the class of checkpoint inhibitors (CPIs), antibodies that unleash the antitumor immune response. After the success in melanoma, numerous clinical trials are being conducted investigating CPIs in lung cancer and mesothelioma. The programmed death protein (PD) 1-PD ligand 1/2 pathway and cytotoxic T lymphocyte-associated protein 4 are currently the most studied immunotherapeutic targets in these malignancies. In non-small cell lung cancer, anti-PD-1 antibodies have become part of the approved treatment arsenal. In small cell lung cancer and mesothelioma, the efficacy of checkpoint inhibition has not yet been proven. In this Concise Clinical Review, an overview of the landmark clinical trials investigating checkpoint blockade in lung cancer and mesothelioma is provided. Because response rates are around 20% in the majority of clinical trials, there is much room for improvement. Predictive biomarkers are therefore essential to fully develop the potential of CPIs. To increase efficacy, multiple clinical trials investigating the combination of cytotoxic T lymphocyte-associated protein 4 inhibitors and PD-1/PD ligand 1 blockade in lung cancer and mesothelioma are being conducted. Given the potential benefit of immunotherapy, implementation of current and new knowledge in trial designs and interpretation of results is essential for moving forward.

  20. Partial and transient reduction of glycolysis by PFKFB3 blockade reduces pathological angiogenesis. (United States)

    Schoors, Sandra; De Bock, Katrien; Cantelmo, Anna Rita; Georgiadou, Maria; Ghesquière, Bart; Cauwenberghs, Sandra; Kuchnio, Anna; Wong, Brian W; Quaegebeur, Annelies; Goveia, Jermaine; Bifari, Francesco; Wang, Xingwu; Blanco, Raquel; Tembuyser, Bieke; Cornelissen, Ivo; Bouché, Ann; Vinckier, Stefan; Diaz-Moralli, Santiago; Gerhardt, Holger; Telang, Sucheta; Cascante, Marta; Chesney, Jason; Dewerchin, Mieke; Carmeliet, Peter


    Strategies targeting pathological angiogenesis have focused primarily on blocking vascular endothelial growth factor (VEGF), but resistance and insufficient efficacy limit their success, mandating alternative antiangiogenic strategies. We recently provided genetic evidence that the glycolytic activator phosphofructokinase-2/fructose-2,6-bisphosphatase 3 (PFKFB3) promotes vessel formation but did not explore the antiangiogenic therapeutic potential of PFKFB3 blockade. Here, we show that blockade of PFKFB3 by the small molecule 3-(3-pyridinyl)-1-(4-pyridinyl)-2-propen-1-one (3PO) reduced vessel sprouting in endothelial cell (EC) spheroids, zebrafish embryos, and the postnatal mouse retina by inhibiting EC proliferation and migration. 3PO also suppressed vascular hyperbranching induced by inhibition of Notch or VEGF receptor 1 (VEGFR1) and amplified the antiangiogenic effect of VEGF blockade. Although 3PO reduced glycolysis only partially and transiently in vivo, this sufficed to decrease pathological neovascularization in ocular and inflammatory models. These insights may offer therapeutic antiangiogenic opportunities. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Durable antitumor responses to CD47 blockade require adaptive immune stimulation. (United States)

    Sockolosky, Jonathan T; Dougan, Michael; Ingram, Jessica R; Ho, Chia Chi M; Kauke, Monique J; Almo, Steven C; Ploegh, Hidde L; Garcia, K Christopher


    Therapeutic antitumor antibodies treat cancer by mobilizing both innate and adaptive immunity. CD47 is an antiphagocytic ligand exploited by tumor cells to blunt antibody effector functions by transmitting an inhibitory signal through its receptor signal regulatory protein alpha (SIRPα). Interference with the CD47-SIRPα interaction synergizes with tumor-specific monoclonal antibodies to eliminate human tumor xenografts by enhancing macrophage-mediated antibody-dependent cellular phagocytosis (ADCP), but synergy between CD47 blockade and ADCP has yet to be demonstrated in immunocompetent hosts. Here, we show that CD47 blockade alone or in combination with a tumor-specific antibody fails to generate antitumor immunity against syngeneic B16F10 tumors in mice. Durable tumor immunity required programmed death-ligand 1 (PD-L1) blockade in combination with an antitumor antibody, with incorporation of CD47 antagonism substantially improving response rates. Our results highlight an underappreciated contribution of the adaptive immune system to anti-CD47 adjuvant therapy and suggest that targeting both innate and adaptive immune checkpoints can potentiate the vaccinal effect of antitumor antibody therapy.

  2. On Disruption of Fear Memory by Reconsolidation Blockade: Evidence from Cannabidiol Treatment (United States)

    Stern, Cristina A J; Gazarini, Lucas; Takahashi, Reinaldo N; Guimarães, Francisco S; Bertoglio, Leandro J


    The search for reconsolidation blockers may uncover clinically relevant drugs for disrupting memories of significant stressful life experiences, such as those underlying the posttraumatic stress disorder. Considering the safety of systemically administered cannabidiol (CBD), the major non-psychotomimetic component of Cannabis sativa, to animals and humans, the present study sought to investigate whether and how this phytocannabinoid (3–30 mg/kg intraperitoneally; i.p.) could mitigate an established memory, by blockade of its reconsolidation, evaluated in a contextual fear-conditioning paradigm in rats. We report that CBD is able to disrupt 1- and 7-days-old memories when administered immediately, but not 6 h, after their retrieval for 3 min, with the dose of 10 mg/kg being the most effective. This effect persists in either case for at least 1 week, but is prevented when memory reactivation was omitted, or when the cannabinoid type-1 receptors were antagonized selectively with AM251 (1.0 mg/kg). Pretreatment with the serotonin type-1A receptor antagonist WAY100635, however, failed to block CBD effects. These results highlight that recent and older fear memories are equally vulnerable to disruption induced by CBD through reconsolidation blockade, with a consequent long-lasting relief in contextual fear-induced freezing. Importantly, this CBD effect is dependent on memory reactivation, restricted to time window of <6 h, and is possibly dependent on cannabinoid type-1 receptor-mediated signaling mechanisms. We also observed that the fear memories disrupted by CBD treatment do not show reinstatement or spontaneous recovery over 22 days. These findings support the view that reconsolidation blockade, rather than facilitated extinction, accounts for the aforementioned CBD results in our experimental conditions. PMID:22549120

  3. Costimulatory signal blockade in murine relapsing experimental autoimmune encephalomyelitis

    DEFF Research Database (Denmark)

    Schaub, M; Issazadeh-Navikas, Shohreh; Stadlbauer, T H


    Blockade of the CD28-B7 or CD40L-CD40 T cell costimulatory signals prevents induction of experimental autoimmune encephalomyelitis (EAE). However, the effect of simultaneous blockade of these signals in EAE is unknown. We show that administration of either MR1 (to block CD40L) or CTLA4Ig (to block...

  4. Antilocalization of Coulomb Blockade in a Ge-Si Nanowire

    DEFF Research Database (Denmark)

    Higginbotham, Andrew P.; Kuemmeth, Ferdinand; Larsen, Thorvald Wadum


    The distribution of Coulomb blockade peak heights as a function of magnetic field is investigated experimentally in a Ge-Si nanowire quantum dot. Strong spin-orbit coupling in this hole-gas system leads to antilocalization of Coulomb blockade peaks, consistent with theory. In particular, the peak...

  5. Axillary plexus blockade in microvascular surgery, a steal phenomenon?

    NARCIS (Netherlands)

    J.F.A. van der Werff (John); G. Medici; S.E.R. Hovius (Steven); A. Kusuma (Ari)


    textabstractA case report is presented of an axillary plexus blockade following a second toe-to-hand transfer. After completion of the microvascular anastomoses and restoration of blood flow to the transplanted toe, the axillary plexus blockade was started. Together with the vasodilation of the hand

  6. Receptor-selective changes in mu-, delta- and kappa-opioid receptors after chronic naltrexone treatment in mice

    NARCIS (Netherlands)

    Lesscher, HMB; Bailey, Alexis; Burbach, JPH; van Ree, JM; Kitchen, [No Value; Gerrits, MAFM

    Chronic treatment with the opioid antagonist naltrexone induces functional supersensitivity to opioid agonists, which may be explained by receptor up-regulation induced by opioid receptor blockade. In the present study, the levels of opioid receptor subtypes through the brain of mice were determined

  7. PD-1 blockade in chronically HIV-1-infected humanized mice suppresses viral loads.

    Directory of Open Access Journals (Sweden)

    Edward Seung

    Full Text Available An estimated 34 million people are living with HIV worldwide (UNAIDS, 2012, with the number of infected persons rising every year. Increases in HIV prevalence have resulted not only from new infections, but also from increases in the survival of HIV-infected persons produced by effective anti-retroviral therapies. Augmentation of anti-viral immune responses may be able to further increase the survival of HIV-infected persons. One strategy to augment these responses is to reinvigorate exhausted anti-HIV immune cells present in chronically infected persons. The PD-1-PD-L1 pathway has been implicated in the exhaustion of virus-specific T cells during chronic HIV infection. Inhibition of PD-1 signaling using blocking anti-PD-1 antibodies has been shown to reduce simian immunodeficiency virus (SIV loads in monkeys. We now show that PD-1 blockade can improve control of HIV replication in vivo in an animal model. BLT (Bone marrow-Liver-Thymus humanized mice chronically infected with HIV-1 were treated with an anti-PD-1 antibody over a 10-day period. The PD-1 blockade resulted in a very significant 45-fold reduction in HIV viral loads in humanized mice with high CD8(+ T cell expression of PD-1, compared to controls at 4 weeks post-treatment. The anti-PD-1 antibody treatment also resulted in a significant increase in CD8(+ T cells. PD-1 blockade did not affect T cell expression of other inhibitory receptors co-expressed with PD-1, including CD244, CD160 and LAG-3, and did not appear to affect virus-specific humoral immune responses. These data demonstrate that inhibiting PD-1 signaling can reduce HIV viral loads in vivo in the humanized BLT mouse model, suggesting that blockade of the PD-1-PD-L1 pathway may have therapeutic potential in the treatment of patients already infected with the AIDS virus.

  8. Ifenprodil for prolonged spinal blockades of motor function and nociception in rats. (United States)

    Chen, Yu-Wen; Chiu, Chong-Chi; Wang, Jieh-Neng; Hung, Ching-Hsia; Wang, Jhi-Joung


    The aim of the study was to compare the proposed spinal anesthetic effect of ifenprodil, an a1 adrenergic receptor antagonist, with that of the long-acting local anesthetic bupivacaine. After intrathecally injecting the rats with five different doses of each drug, the dose-response curves of ifenprodil and bupivacaine were constructed to obtain the 50% effective dose (ED50). The spinal blockades of motor function and nociception of ifenprodil were compared with that of bupivacaine. We showed that either ifenprodil or bupivacaine produced spinal blockades of motor function and nociception dose-dependently. On the ED50 basis, the potency of ifenprodil (0.42(0.38-0.46) μmol; 0.40(0.36-0.44) μmol) was equal (p>0.05) to that of bupivacaine (0.38(0.36-0.40) μmol; 0.35(0.32-0.38) μmol) in motor function and nociception, respectively. At the equianesthetic doses (ED25, ED50, and ED75), duration produced by ifenprodil was greater than that produced by bupivacaine in motor function and nociception (p<0.05 for the differences). Furthermore, both ifenprodil and bupivacaine showed longer duration of sensory blockade than that of motor blockade (p<0.05 for the differences). The resulting data demonstrated that ifenprodil produces a dose-dependent local anesthetic effect in spinal anesthesia. Ifenprodil shows a more sensory-selective duration of action over motor block, whereas the duration of anesthesia is significantly longer with ifenprodil than with bupivacaine. Copyright © 2015 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

  9. Moderate dietary sodium restriction added to angiotensin converting enzyme inhibition compared with dual blockade in lowering proteinuria and blood pressure : randomised controlled trial

    NARCIS (Netherlands)

    Slagman, Maartje C. J.; Waanders, Femke; Hemmelder, Marc H.; Woittiez, Arend-Jan; Janssen, Wilbert M. T.; Lambers Heerspink, Hiddo J.; Navis, Gerjan; Laverman, Gozewijn D.


    Objective To compare the effects on proteinuria and blood pressure of addition of dietary sodium restriction or angiotensin receptor blockade at maximum dose, or their combination, in patients with non-diabetic nephropathy receiving background treatment with angiotensin converting enzyme (ACE)

  10. Deep Neuromuscular Blockade Improves Laparoscopic Surgical Conditions

    DEFF Research Database (Denmark)

    Rosenberg, Jacob; Herring, W Joseph; Blobner, Manfred


    Hg; 'standard') insufflation pressure in a 2 × 2 factorial design. Primary endpoint was surgeon's overall satisfaction with surgical conditions, rated at end of surgery using an 11-point numerical scale. Post-operative pain scores were also evaluated. Data were analyzed using analysis of covariance. RESULTS......INTRODUCTION: Sustained deep neuromuscular blockade (NMB) during laparoscopic surgery may facilitate optimal surgical conditions. This exploratory study assessed whether deep NMB improves surgical conditions and, in doing so, allows use of lower insufflation pressures during laparoscopic......: Of 127 randomized patients, 120 had evaluable data for the primary endpoint. Surgeon's score of overall satisfaction with surgical conditions was significantly higher with deep versus moderate NMB indicated by a least-square mean difference of 1.1 points (95% confidence interval 0.1-2.0; P = 0...

  11. Deep Neuromuscular Blockade Improves Laparoscopic Surgical Conditions

    DEFF Research Database (Denmark)

    Rosenberg, Jacob; Herring, W Joseph; Blobner, Manfred


    INTRODUCTION: Sustained deep neuromuscular blockade (NMB) during laparoscopic surgery may facilitate optimal surgical conditions. This exploratory study assessed whether deep NMB improves surgical conditions and, in doing so, allows use of lower insufflation pressures during laparoscopic......Hg; 'standard') insufflation pressure in a 2 × 2 factorial design. Primary endpoint was surgeon's overall satisfaction with surgical conditions, rated at end of surgery using an 11-point numerical scale. Post-operative pain scores were also evaluated. Data were analyzed using analysis of covariance. RESULTS......: Of 127 randomized patients, 120 had evaluable data for the primary endpoint. Surgeon's score of overall satisfaction with surgical conditions was significantly higher with deep versus moderate NMB indicated by a least-square mean difference of 1.1 points (95% confidence interval 0.1-2.0; P = 0...

  12. Beta blockade and physical training in rats. (United States)

    Harri, M


    Beta adrenergic blocking agents are widely used in the treatment of hypertension. Recent findings indicate that long-term physical training also could reduce elevated blood pressure and many physicians therefore recommend their patients to include physical training in their everyday program. However, it is not known whether a combination of beta blockade and physical training influences the responses of an organism to physical training. This problem was investigated using laboratory rats as an experimental animal model. Both swimming and running training were used, and a group of animals was trained without any medication while the other group performed their daily training session under the influence of 10 mg/kg of propranolol. Some of the effects produced by swimming training, such as hypertrophy of brown adipose tissue and heart muscle, resting bradycardia, increased tachycardic and tail skin temperature responses to isoprenaline, increased calorigenic response to noradrenaline and delayed cooling rate in cold water were similar to those produced by cold acclimation or repeated noradrenaline injections. It is thus tempting to conclude that the training-induced release of noradrenaline was responsible for the changes mentioned. Propranolol, when associated with the training, effectively hampered these changes. Running training increased the activity of oxidative enzymes in the skeletal muscle much more than did swimming training or repeated noradrenaline injections. Furthermore, running training neither induced hypertrophy of the brown fat nor enhanced calorigenic response to noradrenaline; it even led to enhanced rate of body cooling in cold water. Therefore the adaptive changes caused by running training most probably are not due to cold acclimation effects in spite of that propranolol, when associated with the running sessions, antagonized the development of running-induced changes, too. Some of these changes, such as cardiomegaly, training bradycardia and

  13. Thermal decay of Coulomb blockade oscillations (United States)

    Idrisov, Edvin G.; Levkivskyi, Ivan P.; Sukhorukov, Eugene V.


    We study transport properties and the charge quantization phenomenon in a small metallic island connected to the leads through two quantum point contacts (QPCs). The linear conductance is calculated perturbatively with respect to weak tunneling and weak backscattering at QPCs as a function of the temperature T and gate voltage. The conductance shows Coulomb blockade (CB) oscillations as a function of the gate voltage that decay with the temperature as a result of thermally activated fluctuations of the charge in the island. The regimes of quantum T ≪EC and thermal T ≫EC fluctuations are considered, where EC is the charging energy of an isolated island. Our predictions for CB oscillations in the quantum regime coincide with previous findings by Furusaki and Matveev [Phys. Rev. B 52, 16676 (1995), 10.1103/PhysRevB.52.16676]. In the thermal regime the visibility of Coulomb blockade oscillations decays with the temperature as √{T /EC }exp(-π2T /EC) , where the exponential dependence originates from the thermal averaging over the instant charge fluctuations, while the prefactor has a quantum origin. This dependence does not depend on the strength of couplings to the leads. The differential capacitance, calculated in the case of a single tunnel junction, shows the same exponential decay, however the prefactor is linear in the temperature. This difference can be attributed to the nonlocality of the quantum effects. Our results agree with the recent experiment [Nature (London) 536, 58 (2016), 10.1038/nature19072] in the whole range of the parameter T /EC .

  14. Ionic Coulomb Blockade and Resonant Conduction in Biological Ion Channels

    CERN Document Server

    Kaufman, I Kh; Eisenberg, R S


    The conduction and selectivity of calcium/sodium ion channels are described in terms of ionic Coulomb blockade, a phenomenon based on charge discreteness and an electrostatic model of an ion channel. This novel approach provides a unified explanation of numerous observed and modelled conductance and selectivity phenomena, including the anomalous mole fraction effect and discrete conduction bands. Ionic Coulomb blockade and resonant conduction are similar to electronic Coulomb blockade and resonant tunnelling in quantum dots. The model is equally applicable to other nanopores.

  15. Pauli Spin Blockade and the Ultrasmall Magnetic Field Effect

    KAUST Repository

    Danon, Jeroen


    Based on the spin-blockade model for organic magnetoresistance, we present an analytic expression for the polaron-bipolaron transition rate, taking into account the effective nuclear fields on the two sites. We reveal the physics behind the qualitatively different magnetoconductance line shapes observed in experiment, as well as the ultrasmall magnetic field effect (USFE). Since our findings agree in detail with recent experiments, they also indirectly provide support for the spin-blockade interpretation of organic magnetoresistance. In addition, we predict the existence of a similar USFE in semiconductor double quantum dots tuned to the spin-blockade regime.

  16. Regulation of myeloid cells by activated T cells determines the efficacy of PD-1 blockade. (United States)

    Eissler, Nina; Mao, Yumeng; Brodin, David; Reuterswärd, Philippa; Andersson Svahn, Helene; Johnsen, John Inge; Kiessling, Rolf; Kogner, Per


    Removal of immuno-suppression has been reported to enhance antitumor immunity primed by checkpoint inhibitors. Although PD-1 blockade failed to control tumor growth in a transgenic murine neuroblastoma model, concurrent inhibition of colony stimulating factor 1 receptor (CSF-1R) by BLZ945 reprogrammed suppressive myeloid cells and significantly enhanced therapeutic effects. Microarray analysis of tumor tissues identified a significant increase of T-cell infiltration guided by myeloid cell-derived chemokines CXCL9, 10, and 11. Blocking the responsible chemokine receptor CXCR3 hampered T-cell infiltration and reduced antitumor efficacy of the combination therapy. Multivariate analysis of 59 immune-cell parameters in tumors and spleens detected the correlation between PD-L1-expressing myeloid cells and tumor burden. In vitro, anti-PD-1 antibody Nivolumab in combination with BLZ945 increased the activation of primary human T and NK cells. Importantly, we revealed a previously uncharacterized pathway, in which T cells secreted M-CSF upon PD-1 blockade, leading to enhanced suppressive capacity of monocytes by upregulation of PD-L1 and purinergic enzymes. In multiple datasets of neuroblastoma patients, gene expression of CD73 correlated strongly with myeloid cell markers CD163 and CSF-1R in neuroblastoma tumors, and associated with worse survival in high-risk patients. Altogether, our data reveal the dual role of activated T cells on myeloid cell functions and provide a rationale for the combination therapy of anti-PD-1 antibody with CSF-1R inhibitor.

  17. Radiotherapy and immune checkpoint blockades: a snapshot in 2016

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Tae Yool [Dept. of Radiation Oncology, Hallym University Chuncheon Sacred Heart Hospital, Chuncheon (Korea, Republic of); Kim, In Ah [Dept. of Radiation Oncology, Seoul National University College of Medicine, Seoul (Korea, Republic of)


    Immune checkpoint blockades including monoclonal antibodies (mAbs) of cytotoxic T-lymphocyte antigen-4 (CTLA-4), programmed death-1 (PD-1), and programmed death-ligand 1 (PD-L1) have been emerged as a promising anticancer therapy. Several immune checkpoint blockades have been approved by US Food and Drug Administration (FDA), and have shown notable success in clinical trials for patients with advanced melanoma and non-small cell lung cancer. Radiotherapy is a promising combination partner of immune checkpoint blockades due to its potent pro-immune effect. This review will cover the current issue and the future perspectives for combined with radiotherapy and immune checkpoint blockades based upon the available preclinical and clinical data.

  18. Transport Through a Coulomb Blockaded Majorana Nanowire (United States)

    Zazunov, Alex; Egger, Reinhold; Yeyati, Alfredo Levy; Hützen, Roland; Braunecker, Bernd

    In one-dimensional (1D) quantum wires with strong spin-orbit coupling and a Zeeman field, a superconducting substrate can induce zero-energy Majorana bound states located near the ends of the wire. We study electronic properties when such a wire is contacted by normal metallic or superconducting electrodes. A special attention is devoted to Coulomb blockade effects. We analyze the "Majorana single-charge transistor" (MSCT), i.e., a floating Majorana wire contacted by normal metallic source and drain contacts, where charging effects are important. We describe Coulomb oscillations in this system and predict that Majorana fermions could be unambiguously detected by the emergence of sideband peaks in the nonlinear differential conductance. We also study a superconducting variant of the MSCT setup with s-wave superconducting (instead of normal-conducting) leads. In the noninteracting case, we derive the exact current-phase relation (CPR) and find π-periodic behavior with negative critical current for weak tunnel couplings. Charging effects then cause the anomalous CPR I(\\varphi ) = Ic\\cos \\varphi, where the parity-sensitive critical current I c provides a signature for Majorana states.

  19. Local renin-angiotensin system regulates the differentiation of mesenchymal stem cells into insulin-producing cells through angiotensin type 2 receptor. (United States)

    Sadik, Nermin Abdel-Hamid; Metwally, Nadia Said; Shaker, Olfat Gamil; Soliman, Mahmoud Sanad; Mohamed, Ahmed Abdelaziz; Abdelmoaty, Mai Mohamed


    Differentiation of stem cells into insulin-producing cells (IPCs) suitable for therapeutic transplantation offers a desperately needed approach for the diabetic patients. Elucidation of the molecular mechanisms during the differentiation of mesenchymal stem cells (MSCs) into IPCs assists the successful production of IPCs and provides an important insight into the improvement of the role of MSCs as a therapeutic tool for diabetes mellitus (DM). The present study aimed to investigate the role of local renin-angiotensin system (RAS) on MSCs differentiation into IPCs by measuring the expression of local RAS in MSCs during the differentiation into IPCs and assessing the effect of angiotensin type 1 receptor (AT1R) blocker and angiotensin type 2 receptor (AT2R) blocker on the differentiation process. Our data showed that the differentiation of MSCs into IPCs was associated with an increase in cellular angiotensinogen, angiotensin-converting enzyme (ACE), renin, and AT2R expression and undetectable expression of AT1R. The net effect was an increase in cellular angiotensin II (Ang II) during the differentiation process. AT1R blockade allowed the differentiation of MSCs into IPCs, whereas AT2R blockade alone and blockade of both AT1R and AT2R inhibited the differentiation of MSCs into IPCs. Our data demonstrated an important role of local RAS in the regulation of MSCs differentiation into IPCs and that Ang II mainly orchestrates this role through AT2R activation. Copyright © 2017 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

  20. Beneficial Effects of the Activation of the Angiotensin-(1–7) Mas Receptor in a Murine Model of Adriamycin-Induced Nephropathy (United States)

    Silveira, Kátia Daniela; Barroso, Lívia Corrêa; Vieira, Angélica Thomáz; Cisalpino, Daniel; Lima, Cristiano Xavier; Bader, Michael; Arantes, Rosa Maria Esteves; dos Santos, Robson Augusto Souza


    Angiotensin-(1–7) [Ang-(1–7)] is a biologically active heptapeptide that may counterbalance the physiological actions of angiotensin II (Ang II) within the renin-angiotensin system (RAS). Here, we evaluated whether activation of the Mas receptor with the oral agonist, AVE 0991, would have renoprotective effects in a model of adriamycin (ADR)-induced nephropathy. We also evaluated whether the Mas receptor contributed for the protective effects of treatment with AT1 receptor blockers. ADR (10 mg/kg) induced significant renal injury and dysfunction that was maximal at day 14 after injection. Treatment with the Mas receptor agonist AVE 0991 improved renal function parameters, reduced urinary protein loss and attenuated histological changes. Renoprotection was associated with reduction in urinary levels of TGF-β. Similar renoprotection was observed after treatment with the AT1 receptor antagonist, Losartan. AT1 and Mas receptor mRNA levels dropped after ADR administration and treatment with losartan reestablished the expression of Mas receptor and increased the expression of ACE2. ADR-induced nephropathy was similar in wild type (Mas+/+) and Mas knockout (Mas−/−) mice, suggesting there was no endogenous role for Mas receptor activation. However, treatment with Losartan was able to reduce renal injury only in Mas+/+, but not in Mas−/− mice. Therefore, these findings suggest that exogenous activation of the Mas receptor protects from ADR-induced nephropathy and contributes to the beneficial effects of AT1 receptor blockade. Medications which target specifically the ACE2/Ang-(1–7)/Mas axis may offer new therapeutic opportunities to treat human nephropathies. PMID:23762470

  1. Beneficial effects of the activation of the angiotensin-(1-7) MAS receptor in a murine model of adriamycin-induced nephropathy. (United States)

    Silveira, Kátia Daniela; Barroso, Lívia Corrêa; Vieira, Angélica Thomáz; Cisalpino, Daniel; Lima, Cristiano Xavier; Bader, Michael; Arantes, Rosa Maria Esteves; Dos Santos, Robson Augusto Souza; Simões-E-Silva, Ana Cristina; Teixeira, Mauro Martins


    Angiotensin-(1-7) [Ang-(1-7)] is a biologically active heptapeptide that may counterbalance the physiological actions of angiotensin II (Ang II) within the renin-angiotensin system (RAS). Here, we evaluated whether activation of the Mas receptor with the oral agonist, AVE 0991, would have renoprotective effects in a model of adriamycin (ADR)-induced nephropathy. We also evaluated whether the Mas receptor contributed for the protective effects of treatment with AT1 receptor blockers. ADR (10 mg/kg) induced significant renal injury and dysfunction that was maximal at day 14 after injection. Treatment with the Mas receptor agonist AVE 0991 improved renal function parameters, reduced urinary protein loss and attenuated histological changes. Renoprotection was associated with reduction in urinary levels of TGF-β. Similar renoprotection was observed after treatment with the AT1 receptor antagonist, Losartan. AT1 and Mas receptor mRNA levels dropped after ADR administration and treatment with losartan reestablished the expression of Mas receptor and increased the expression of ACE2. ADR-induced nephropathy was similar in wild type (Mas(+/+) ) and Mas knockout (Mas (-/-)) mice, suggesting there was no endogenous role for Mas receptor activation. However, treatment with Losartan was able to reduce renal injury only in Mas(+/+) , but not in Mas (-/-) mice. Therefore, these findings suggest that exogenous activation of the Mas receptor protects from ADR-induced nephropathy and contributes to the beneficial effects of AT1 receptor blockade. Medications which target specifically the ACE2/Ang-(1-7)/Mas axis may offer new therapeutic opportunities to treat human nephropathies.

  2. Regression of cardiac hypertrophy in the SHR by combined renin-angiotensin system blockade and dietary sodium restriction

    Directory of Open Access Journals (Sweden)

    Emad Abro


    Full Text Available Altered operation of the renin-angiotensin-aldosterone system (RAAS and dietary sodium intake have been identified as independent risk factors for cardiac hypertrophy. The way in which sodium intake and the operation of the renin-angiotensin-aldosterone system interact in the pathogenesis of cardiac hypertrophy is poorly understood. The aims of this study were to investigate the cardiac effects of the renin-angiotensin system (RAS blockade in the spontaneously hypertensive rat (SHR, using co-treatment with an angiotensin II receptor blocker (ARB and an angiotensin-converting enzyme (ACE inhibitor with different sodium intakes. Our experiments with SHR show that, at high levels of sodium intake (4.0%, aggressive RAS blockade treatment with candesartan (3 mg/kg and perindopril (6 mg/kg does not result in regression of cardiac hypertrophy. In contrast, RAS blockade coupled with reduced sodium diet (0.2% significantly regresses cardiac hypertrophy, impairs animal growth and is associated with elevated plasma renin and dramatically suppressed plasma angiotensinogen levels. Histological analyses indicate that the differential effect of reduced sodium on heart growth during RAS blockade is not associated with any change in myocardial interstitial collagen, but reflects modification of cellular geometry. Dimensional measurements of enzymatically-isolated ventricular myocytes show that, in the RAS blocked, reduced sodium group, myocyte length and width were decreased by about 16—19% compared with myocytes from the high sodium treatment group. Our findings highlight the importance of `titrating' sodium intake with combined RAS blockade in the clinical setting to optimise therapeutic benefit.

  3. Endothelin Blockade in Diabetic Kidney Disease

    Directory of Open Access Journals (Sweden)

    Lidia Anguiano


    Full Text Available Diabetic kidney disease (DKD remains the most common cause of chronic kidney disease and multiple therapeutic agents, primarily targeted at the renin-angiotensin system, have been assessed. Their only partial effectiveness in slowing down progression to end-stage renal disease, points out an evident need for additional effective therapies. In the context of diabetes, endothelin-1 (ET-1 has been implicated in vasoconstriction, renal injury, mesangial proliferation, glomerulosclerosis, fibrosis and inflammation, largely through activation of its endothelin A (ETA receptor. Therefore, endothelin receptor antagonists have been proposed as potential drug targets. In experimental models of DKD, endothelin receptor antagonists have been described to improve renal injury and fibrosis, whereas clinical trials in DKD patients have shown an antiproteinuric effect. Currently, its renoprotective effect in a long-time clinical trial is being tested. This review focuses on the localization of endothelin receptors (ETA and ETB within the kidney, as well as the ET-1 functions through them. In addition, we summarize the therapeutic benefit of endothelin receptor antagonists in experimental and human studies and the adverse effects that have been described.

  4. Circadian rhythm disruption by a novel running wheel: roles of exercise and arousal in blockade of the luteinizing hormone surge. (United States)

    Duncan, Marilyn J; Franklin, Kathleen M; Peng, Xiaoli; Yun, Christopher; Legan, Sandra J


    Exposure of proestrous Syrian hamsters to a new room, cage, and novel running wheel blocks the luteinizing hormone (LH) surge until the next day in ~75% of hamsters [1]. The studies described here tested the hypotheses that 1) exercise and/or 2) orexinergic neurotransmission mediate novel wheel blockade of the LH surge and circadian phase advances. Female hamsters were exposed to a 14L:10D photoperiod and activity rhythms were monitored with infra-red detectors. In Expt. 1, to test the effect of exercise, hamsters received jugular cannulae and on the next day, proestrus (Day 1), shortly before zeitgeber time 5 (ZT 5, 7h before lights-off) the hamsters were transported to the laboratory. After obtaining a blood sample at ZT 5, the hamsters were transferred to a new cage with a novel wheel that was either freely rotating (unlocked), or locked until ZT 9, and exposed to constant darkness (DD). Blood samples were collected hourly for 2days from ZT 5-11 under red light for determination of plasma LH levels by radioimmunoassay. Running rhythms were monitored continuously for the next 10-14days. The locked wheels were as effective as unlocked wheels in blocking LH surges (no Day 1 LH surge in 6/9 versus 8/8 hamsters, P>0.05) and phase advances in the activity rhythms did not differ between the groups (P=0.28), suggesting that intense exercise is not essential for novel wheel blockade and phase advance of the proestrous LH surge. Expt. 2 tested whether orexin neurotransmission is essential for these effects. Hamsters were treated the same as those in Expt. 1 except that they were injected (i.p.) at ZT 4.5 and 5 with either the orexin 1 receptor antagonist SB334867 (15mg/kg per injection) or vehicle (25% DMSO in 2-hydroxypropyl-beta-cyclodextrin (HCD)). SB-334867 inhibited novel wheel blockade of the LH surge (surges blocked in 2/6 SB334867-injected animals versus 16/18 vehicle-injected animals, Psurge. In conclusion, these studies indicate that novel wheel exposure

  5. Effects of ionotropic glutamate receptor antagonists on rat dural artery diameter in an intravital microscopy model

    DEFF Research Database (Denmark)

    Chan, K Y; Gupta, S; de Vries, R


    During migraine, trigeminal nerves may release calcitonin gene-related peptide (CGRP), inducing cranial vasodilatation and central nociception; hence, trigeminal inhibition or blockade of craniovascular CGRP receptors may prevent this vasodilatation and abort migraine headache. Several preclinical...

  6. Blockade of gap junction hemichannel suppresses disease progression in mouse models of amyotrophic lateral sclerosis and Alzheimer's disease.

    Directory of Open Access Journals (Sweden)

    Hideyuki Takeuchi

    Full Text Available Glutamate released by activated microglia induces excitotoxic neuronal death, which likely contributes to non-cell autonomous neuronal death in neurodegenerative diseases, including amyotrophic lateral sclerosis and Alzheimer's disease. Although both blockade of glutamate receptors and inhibition of microglial activation are the therapeutic candidates for these neurodegenerative diseases, glutamate receptor blockers also perturbed physiological and essential glutamate signals, and inhibitors of microglial activation suppressed both neurotoxic/neuroprotective roles of microglia and hardly affected disease progression. We previously demonstrated that activated microglia release a large amount of glutamate specifically through gap junction hemichannel. Hence, blockade of gap junction hemichannel may be potentially beneficial in treatment of neurodegenerative diseases.In this study, we generated a novel blood-brain barrier permeable gap junction hemichannel blocker based on glycyrrhetinic acid. We found that pharmacologic blockade of gap junction hemichannel inhibited excessive glutamate release from activated microglia in vitro and in vivo without producing notable toxicity. Blocking gap junction hemichannel significantly suppressed neuronal loss of the spinal cord and extended survival in transgenic mice carrying human superoxide dismutase 1 with G93A or G37R mutation as an amyotrophic lateral sclerosis mouse model. Moreover, blockade of gap junction hemichannel also significantly improved memory impairments without altering amyloid β deposition in double transgenic mice expressing human amyloid precursor protein with K595N and M596L mutations and presenilin 1 with A264E mutation as an Alzheimer's disease mouse model.Our results suggest that gap junction hemichannel blockers may represent a new therapeutic strategy to target neurotoxic microglia specifically and prevent microglia-mediated neuronal death in various neurodegenerative diseases.

  7. Intravenous platelet blockade with cangrelor during PCI

    NARCIS (Netherlands)

    Bhatt, Deepak L.; Lincoff, A. Michael; Gibson, C. Michael; Stone, Gregg W.; McNulty, Steven; Montalescot, Gilles; Kleiman, Neal S.; Goodman, Shaun G.; White, Harvey D.; Mahaffey, Kenneth W.; Pollack, Charles V.; Manoukian, Steven V.; Widimsky, Petr; Chew, Derek P.; Cura, Fernando; Manukov, Ivan; Tousek, Frantisek; Jafar, M. Zubair; Arneja, Jaspal; Skerjanec, Simona; Harrington, Robert A.; Bhatt, D. L.; Harrington, R. A.; Lincoff, A. M.; Pollack, C. V.; Gibson, C. M.; Stone, G. W.; Mahaffey, K. W.; Kleiman, N. S.; Montalescot, G.; White, H. D.; Goodman, S. G.; Greenbaum, A.; Simon, D.; Lee, D.; Feit, F.; Dauerman, H.; Gurbel, P.; Berger, P.; Makkar, R.; Becker, R. C.; Manoukian, S.; Jorgova, J.; Chew, D. P.; Storey, R.; Desmet, W.; Cura, F.; Herrmann, H.; Rizik, D.; DeServi, S.; Huber, K.; Jukema, W. J.; Knopf, W.; Steg, P. G.; Schunkert, H.; Widimsky, P.; Betriu, A.; Aylward, P.; Polonestsky, L.; Lima, V.; Kobulia, B.; Navickas, R.; Gasior, Z.; Vasilieva, E.; Bennett, J. M.; Kraiz, I.; Van de Werf, F.; Faxon, D.; Ohman, E. M.; Tijssen, J. G. P.; Verheugt, F.; Weaver, W. D.; Califf, R. M.; Mehta, C.; Hamm, C. W.; Pepine, C. J.; Ware, J.; Wilson, M.; Gorham, C.; Maran, A.; McNulty, S.; Fasteson, D.; Ryan, G.; Bradsher, J.; Connolly, P.; Mehta, R.; Leonardi, S.; Brennan, M.; Patel, M.; Petersen, J.; Bushnel, C.; Jolicoeur, M.; Chan, M.; Dowd, L.; Skinner, P.; Lawrence, G.; Jordon, M.; Dickerson, S.; Meyer, M.; Hartford, S.; Garcia Escudero, Alejandro; Poy, Carlos; Miceli, Miguel; Pocovi, Antonio; Londero, Hugo; Baccaro, Jorge; Polonetsky, Leonid; Karotkin, Aliaksey; Shubau, Leanid; Maffini, Eduardo; Machado, Bruno; Airton, José; Lima, Valter; Martinez Filho, Eulogio; Herdy, Arthur; Tumelero, Rogerio; Precoma, Dalton; Botelho, Roberto; Saad, Jamil; Jatene, Jose; Vilas-Boas, Fabio; Godinho, Antonio; Perin, Marco; Caramori, Paulo; Castro, Iran; Grigorov, Mladen; Milkov, Plamen; Jorgova, Julia; Georgiev, Svetoslav; Rifai, Nizar; Doganov, Alexander; Petrov, Ivo; Hui, William; Lazzam, Charles; Reeves, Francois; Tanguay, Jean-Francois; Richter, Marek; Klimsa, Zdenek; Padour, Michal; Mrozek, Jan; Branny, Marian; Coufal, Zdenek; Simek, Stanislav; Rozsival, Vladimir; Pleva, Leos; Stasek, Josef; Kala, Petr; Groch, Ladislav; Kocka, Viktor; Shaburishvili, Tamaz; Khintibidze, Irakli; Chapidze, Gulnara; Mamatsashvili, Merab; Mohanan, Padinhare; Jain, Rajesh; Parikh, Keyur; Patel, Tejas; Kumar, Sampath; Mehta, Ashwani; Banker, Darshan; Krishna, Lanka; Gadkari, Milind; Joshi, Hasit; Hiremath, Shirish; Grinius, Virgilijus; Norkiene, Sigute; Petrauskiene, Birute; Michels, Rolf; Tjon, Melvin; de Swart, Hans; de Winter, Robbert; White, Harvey; Devlin, Gerard; Abernethey, Malcolm; Osiev, Alexander; Linev, Kirill; Kalinina, Svetlana; Baum, Svetlana; Kosmachova, Elena; Shogenov, Zaur; Markov, Valentin; Boldueva, Svetlana; Barbarash, Olga; Kostenko, Victor; Vasilieva, Elena; Gruzdev, Aleksey; Lusov, Victor; Dovgalevsky, Pavel; Azarin, Oleg; Chernov, Sergey; Smolenskaya, Olga; Duda, Alexey; Fridrich, Viliam; Hranai, Marian; Studencan, Martin; Kurray, Peter; Bennett, John; Blomerus, Pieter; Disler, Laurence; Engelbrecht, Johannes; Klug, Eric; Routier, Robert; Venter, Tjaart; van der Merwe, Nico; Becker, Anthony; Cha, Kwang-Soo; Lee, Seung-Hwan; Han, Sang-Jin; Youn, Tae Jin; Hur, Seung-Ho; Seo, Hong Seog; Park, Hun-Sik; Rhim, Chong-Yun; Pyun, Wook-Bum; Choe, Hyunmin; Jeong, Myung-Ho; Park, Jong-Seon; Shin, Eak-Kyun; Hernández, Felipe; Figueras, Jaume; Hernández, Rosana; López-Minguez, José Ramón; González Juanatey, José Ramón; Palop, Ramón López; Galeote, Guillermo; Chamnarnphol, Noppadol; Buddhari, Wacin; Sansanayudh, Nakarin; Kuanprasert, Srun; Penny, William; Lui, Charles; Grimmett, Garfield; Srinivasan, Venkatraman; Ariani, Kevin; Khan, Waqor; Blankenship, James; Cannon, Louis; Eisenberg, Steven; McLaurin, Brent; Mahoney, Paul; Greenberg, Jerry; Breall, Jeffrey; Chandna, Harish; Hockstad, Eric; Tolerico, Paul; Kao, John; Shroff, Adhir; Nseir, Georges; Greenbaum, Adam; Cohn, Joel; Gogia, Harinder; Nahhas, Ahed; Istfan, Pierre; Orlow, Steve; Spriggs, Douglas; Sklar, Joel; Paulus, Richard; Cochran, David; Smith, Robert; Ferrier, L. Norman; Scott, J. Christopher; Xenopoulos, Nicholaos; Mulumudi, Mahesh; Hoback, James; Ginete, Wilson; Ballard, William; Stella, Joseph; Voeltz, Michele; Staniloae, Cezar; Eaton, Gregory; Griffin, John; Kumar, Krishna; Ebrahimi, Ramin; O'Shaughnessy, Charles; Lundstrom, Lundstrom; Temizer, Dogan; Tam, Kenneth; Suarez, Jose; Raval, Amish; Kaufman, Jay; Brilakis, Emmanouil; Stillabower, Michael; Quealy, Kathleen; Nunez, Boris; Pow, Thomas; Samuels, Bruce; Argenal, Agustin; Srinivas, Vankeepuram; Rosenthal, Andrew; Tummala, Pradyumna; Myers, Paul; LaMarche, Nelson; Chan, Michael; Bach, Richard; Simon, Daniel; Kettelkamp, Richard; Helmy, Tarek; Schaer, Gary; Kosinski, Edward; Buchbinder, Maurice; Sharma, Mukesh; Goodwin, Mark; Horwitz, Phillip; Mann, J. Tift; Holmes, David; Angiolillo, Dominick; Rao, Sunil; Azrin, Michael; Gammon, Roger; Mavromatis, Kreton; Ahmed, Abdel; Kent, Kenneth; Zughaib, Marcel; Westcott, R. Jeffrey; Jain, Ash; Gruberg, Luis; LeGalley, Thomas


    BACKGROUND: Intravenous cangrelor, a rapid-acting, reversible adenosine diphosphate (ADP) receptor antagonist, might reduce ischemic events during percutaneous coronary intervention (PCI). METHODS: In this double-blind, placebo-controlled study, we randomly assigned 5362 patients who had not been

  8. Effect of oxytocin receptor and beta2-adrenoceptor blockade on myometrial oxytocin receptors in parturient rats

    DEFF Research Database (Denmark)

    Engstrom, T.; Bratholm, P.; Vilhardt, Hans


    Pharmacology, metabolism, chemically-induced, adverse-effects, antagonists-and-inhibitors, genetics, physiology, drug-effects, analogs-and-derivatives......Pharmacology, metabolism, chemically-induced, adverse-effects, antagonists-and-inhibitors, genetics, physiology, drug-effects, analogs-and-derivatives...

  9. Dual Blockade of HER-2 Provides a Greater Magnitude of Benefit in Patients With Hormone-Negative Versus Hormone-Positive Breast Cancer. (United States)

    Abramovitz, Mark; Williams, Casey; Loibl, Sibylle; Leyland-Jones, Brian


    The dual small molecule tyrosine kinase inhibitor lapatinib blocks both human epidermal growth factor receptor (HER-1) and human epidermal growth factor receptor 2 (HER-2) tyrosine kinase activity by binding reversibly to the ATP-binding site of the receptor's intracellular domain. Lapatinib, in combination with capecitabine, has been approved in 2007 for the treatment of patients with advanced HER-2 + breast cancer upon progressive disease following standard chemotherapy. Approval was also extended to the treatment of postmenopausal women with advanced hormone receptor (HR)-positive and HER-2-positive breast cancer in 2010. More recently, clinical trials that have investigated the efficacy of dual HER-2 blockade in both the metastatic and neoadjuvant breast cancer settings. For example, in 2013 the European Medicines Agency approved the combination of lapatinib and trastuzumab in HER-2 + /HR - patients. We review the efficacy results from dual HER-2 blockade studies and present new post hoc analysis efficacy data according to HR status. We show that dual blockade of HER-2 appears to provide a greater magnitude of benefit in the HR - versus the HR + subgroup of patients. Finally, we examine the potential of molecularly subtyping HER-2 + tumors using the PAM50 test as a predictor of response to treatment with the combination of trastuzumab and lapatinib. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Sex differences in pain and hypothalamic-pituitary-adrenocortical responses to opioid blockade. (United States)

    al'Absi, Mustafa; Wittmers, Lorentz E; Ellestad, Deanna; Nordehn, Glenn; Kim, Suck Won; Kirschbaum, Clemens; Grant, Jon E


    Sex differences in pain sensitivity and stress reactivity have been well documented. Little is known about the role of the endogenous opioid system in these differences. This study was conducted to compare adrenocortical, pain sensitivity, and blood pressure responses to opioid blockade using naltrexone in men and women. Twenty-six participants completed 2 sessions during which placebo or 50 mg of naltrexone was administered, using a double-blind, counterbalanced design. Thermal pain threshold and heat tolerance were assessed. Participants also rated pain during a 90-second cold pressor test (CPT) and completed the McGill Pain Questionnaire (MPQ) after each pain challenge. Blood and saliva samples and cardiovascular and mood measures were obtained throughout the sessions. Plasma cortisol, adrenocorticotropin, beta endorphin, prolactin, and salivary cortisol levels increased similarly in men and women after naltrexone administration compared with placebo. Women reported more pain during both pain procedures and had lower thermal pain tolerance. In response to naltrexone, women exhibited reduced blood pressure responses and reduced MPQ pain ratings after CPT. No effects of naltrexone on these measures were found in men. Although men and women exhibited similar hormonal responses to opioid receptor blockade, women reported less pain and showed smaller blood pressure responses during CPT. Results suggest differential effects of the endogenous opioid system on pain perception and blood pressure in men and women.

  11. Galectin-3 blockade inhibits cardiac inflammation and fibrosis in experimental hyperaldosteronism and hypertension. (United States)

    Martínez-Martínez, Ernesto; Calvier, Laurent; Fernández-Celis, Amaya; Rousseau, Elodie; Jurado-López, Raquel; Rossoni, Luciana V; Jaisser, Frederic; Zannad, Faiez; Rossignol, Patrick; Cachofeiro, Victoria; López-Andrés, Natalia


    Hypertensive cardiac remodeling is accompanied by molecular inflammation and fibrosis, 2 mechanisms that finally affect cardiac function. At cardiac level, aldosterone promotes inflammation and fibrosis, although the precise mechanisms are still unclear. Galectin-3 (Gal-3), a β-galactoside-binding lectin, is associated with inflammation and fibrosis in the cardiovascular system. We herein investigated whether Gal-3 inhibition could block aldosterone-induced cardiac inflammation and fibrosis and its potential role in cardiac damage associated with hypertension. Aldosterone-salt-treated rats presented hypertension, cardiac inflammation, and fibrosis that were prevented by the pharmacological inhibition of Gal-3 with modified citrus pectin. Cardiac inflammation and fibrosis presented in spontaneously hypertensive rats were prevented by modified citrus pectin treatment, whereas Gal-3 blockade did not modify blood pressure levels. In the absence of blood pressure modifications, Gal-3 knockout mice were resistant to aldosterone-induced cardiac inflammation. In human cardiac fibroblasts, aldosterone increased Gal-3 expression via its mineralocorticoid receptor. Gal-3 and aldosterone enhanced proinflammatory and profibrotic markers, as well as metalloproteinase activities in human cardiac fibroblasts, effects that were not observed in Gal-3-silenced cells treated with aldosterone. In experimental hyperaldosteronism, the increase in Gal-3 expression was associated with cardiac inflammation and fibrosis, alterations that were prevented by Gal-3 blockade independently of blood pressure levels. These data suggest that Gal-3 could be a new molecular mechanism linking cardiac inflammation and fibrosis in situations with high-aldosterone levels, such as hypertension. © 2015 American Heart Association, Inc.

  12. [Ropivacaine (naropin), local anesthetic of choice for epidural blockade]. (United States)

    Ovechkin, A M; Gnezdilov, A V; Syrovegin, A V; Kukushkin, M L; Gasanov, I N


    The purpose of this study, carried out in 132 patients with intense acute radicular pain, was search for an optimal local anesthetic to be used in combination with a steroid for therapeutic epidural blockade. Comparative analysis of analgesia attained by epidural injections of 5 ml 2% lidocaine, 4 ml 0.5% bupivacaine, and 4 ml 1% ropivacaine showed the advantages of the latter drug in stable arrest of radicular pain immediately after injection. The duration of analgesia after blockade was 1.4 +/- 0.5, 3.1 +/- 0.3, and 9.5 +/- 1.2 h, respectively. Use of ropivacaine eliminated the main shortcoming of epidural blockade in the treatment of patients with radicular pain, consisting in temporary pain relapse after discontinuation of the local anesthetic effect before development of antiinflammatory effect of the steroid.

  13. Effects of sugammadex on incidence of postoperative residual neuromuscular blockade

    DEFF Research Database (Denmark)

    Brueckmann, B; Sasaki, N; Grobara, P


    by randomized allocation to sugammadex (2 or 4 mg kg(-1)) or usual care (neostigmine/glycopyrrolate, dosing per usual care practice) for reversal of neuromuscular blockade. Timing of reversal agent administration was based on the providers' clinical judgement. Primary endpoint was the presence of residual...... measured at PACU entry. Zero out of 74 sugammadex patients and 33 out of 76 (43.4%) usual care patients had TOF-Watch® SX-assessed residual neuromuscular blockade at PACU admission (odds ratio 0.0, 95% CI [0-0.06], Pcare patients, 2 also had clinical evidence of partial...... paralysis. Time between reversal agent administration and operating room discharge-readiness was shorter for sugammadex vs usual care (14.7 vs 18.6 min respectively; P=0.02). CONCLUSIONS: After abdominal surgery, sugammadex reversal eliminated residual neuromuscular blockade in the PACU, and shortened...

  14. Erythropoietin blockade inhibits the induction of tumor angiogenesis and progression.

    Directory of Open Access Journals (Sweden)

    Matthew E Hardee

    Full Text Available BACKGROUND: The induction of tumor angiogenesis, a pathologic process critical for tumor progression, is mediated by multiple regulatory factors released by tumor and host cells. We investigated the role of the hematopoietic cytokine erythropoietin as an angiogenic factor that modulates tumor progression. METHODOLOGY/PRINCIPAL FINDINGS: Fluorescently-labeled rodent mammary carcinoma cells were injected into dorsal skin-fold window chambers in mice, an angiogenesis model that allows direct, non-invasive, serial visualization and real-time assessment of tumor cells and neovascularization simultaneously using intravital microscopy and computerized image analysis during the initial stages of tumorigenesis. Erythropoietin or its antagonist proteins were co-injected with tumor cells into window chambers. In vivo growth of cells engineered to stably express a constitutively active erythropoietin receptor EPOR-R129C or the erythropoietin antagonist R103A-EPO were analyzed in window chambers and in the mammary fat pads of athymic nude mice. Co-injection of erythropoietin with tumor cells or expression of EPOR-R129C in tumor cells significantly stimulated tumor neovascularization and growth in window chambers. Co-injection of erythropoietin antagonist proteins (soluble EPOR or anti-EPO antibody with tumor cells or stable expression of antagonist R103A-EPO protein secreted from tumor cells inhibited angiogenesis and impaired tumor growth. In orthotopic tumor xenograft studies, EPOR-R129C expression significantly promoted tumor growth associated with increased expression of Ki67 proliferation antigen, enhanced microvessel density, decreased tumor hypoxia, and increased phosphorylation of extracellular-regulated kinases ERK1/2. R103A-EPO antagonist expression in mammary carcinoma cells was associated with near-complete disruption of primary tumor formation in the mammary fat pad. CONCLUSIONS/SIGNIFICANCE: These data indicate that erythropoietin is an

  15. Multibit CkNOT quantum gates via Rydberg blockade

    DEFF Research Database (Denmark)

    Isenhower, L.; Saffman, Mark; Mølmer, Klaus


    Long range Rydberg blockade interactions have the potential for efficient implementation of quantum gates between multiple atoms. Here we present and analyze a protocol for implementation of a k-atom controlled NOT (CkNOT) neutral atom gate. This gate can be implemented using sequential or simult......Long range Rydberg blockade interactions have the potential for efficient implementation of quantum gates between multiple atoms. Here we present and analyze a protocol for implementation of a k-atom controlled NOT (CkNOT) neutral atom gate. This gate can be implemented using sequential...

  16. Stellate ganglion blockade for analgesia following upper limb surgery.

    LENUS (Irish Health Repository)

    McDonnell, J G


    We report the successful use of a stellate ganglion block as part of a multi-modal postoperative analgesic regimen. Four patients scheduled for orthopaedic surgery following upper limb trauma underwent blockade of the stellate ganglion pre-operatively under ultrasound guidance. Patients reported excellent postoperative analgesia, with postoperative VAS pain scores between 0 and 2, and consumption of morphine in the first 24 h ranging from 0 to 14 mg. While these are preliminary findings, and must be confirmed in a clinical trial, they highlight the potential for stellate ganglion blockade to provide analgesia following major upper limb surgery.

  17. Combination approaches with immune checkpoint blockade in cancer therapy

    Directory of Open Access Journals (Sweden)

    Maarten Swart


    Full Text Available In healthy individuals, immune checkpoint molecules prevent autoimmune responses and limit immune cell-mediated tissue damage. Tumors frequently exploit these molecules to evade eradication by the immune system. Over the past years, immune checkpoint blockade of cytotoxic T lymphocyte antigen-4 (CTLA-4 and programmed death-1 (PD-1 emerged as promising strategies to activate anti-tumor cytotoxic T cell responses. Although complete regression and long-term survival is achieved in some patients, not all patients respond. This review describes promising, novel combination approaches involving immune checkpoint blockade, aimed at increasing response-rates to the single treatments.

  18. PD-1 Blockade Expands Intratumoral Memory T Cells

    DEFF Research Database (Denmark)

    Ribas, Antoni; Shin, Daniel Sanghoon; Zaretsky, Jesse


    Tumor responses to programmed cell death protein 1 (PD-1) blockade therapy are mediated by T cells, which we characterized in 102 tumor biopsies obtained from 53 patients treated with pembrolizumab, an antibody to PD-1. Biopsies were dissociated, and single-cell infiltrates were analyzed by multi...... with regressing melanoma. In conclusion, PD-1 blockade increases the frequency of T cells, B cells, and myeloid-derived suppressor cells in tumors, with the CD8+ effector memory T-cell subset being the major T-cell phenotype expanded in patients with a response to therapy....

  19. Timing of CSF-1/CSF-1R signaling blockade is critical to improving responses to CTLA-4 based immunotherapy. (United States)

    Holmgaard, Rikke B; Brachfeld, Alexandra; Gasmi, Billel; Jones, David R; Mattar, Marissa; Doman, Thompson; Murphy, Mary; Schaer, David; Wolchok, Jedd D; Merghoub, Taha


    Colony stimulating factor-1 (CSF-1) is produced by a variety of cancers and recruits myeloid cells that suppress antitumor immunity, including myeloid-derived suppressor cells (MDSCs.) Here, we show that both CSF-1 and its receptor (CSF-1R) are frequently expressed in tumors from cancer patients, and that this expression correlates with tumor-infiltration of MDSCs. Furthermore, we demonstrate that these tumor-infiltrating MDSCs are highly immunosuppressive but can be reprogrammed toward an antitumor phenotype in vitro upon CSF-1/CSF-1R signaling blockade. Supporting these findings, we show that inhibition of CSF-1/CSF-1R signaling using an anti-CSF-1R antibody can regulate both the number and the function of MDSCs in murine tumors in vivo. We further find that treatment with anti-CSF-1R antibody induces antitumor T-cell responses and tumor regression in multiple tumor models when combined with CTLA-4 blockade therapy. However, this occurs only when administered after or concurrent with CTLA-4 blockade, indicating that timing of each therapeutic intervention is critical for optimal antitumor responses. Importantly, MDSCs present within murine tumors after CTLA-4 blockade showed increased expression of CSF-1R and were capable of suppressing T cell proliferation, and CSF-1/CSF-1R expression in the human tumors was not reduced after treatment with CTLA-4 blockade immunotherapy. Taken together, our findings suggest that CSF-1R-expressing MDSCs can be targeted to modulate the tumor microenvironment and that timing of CSF-1/CSF-1R signaling blockade is critical to improving responses to checkpoint based immunotherapy. Infiltration by immunosuppressive myeloid cells contributes to tumor immune escape and can render patients resistant or less responsive to therapeutic intervention with checkpoint blocking antibodies. Our data demonstrate that blocking CSF-1/CSF-1R signaling using a monoclonal antibody directed to CSF-1R can regulate both the number and function of tumor

  20. Blockade of GM-CSF pathway induced sustained suppression of myeloid and T cell activities in rheumatoid arthritis. (United States)

    Guo, Xiang; Higgs, Brandon W; Bay-Jensen, Anne-Christine; Wu, Yuling; Karsdal, Morten A; Kuziora, Michael; Godwood, Alex; Close, David; Ryan, Patricia C; Roskos, Lorin K; White, Wendy I


    Targeting the granulocyte-macrophage colony-stimulating factor (GM-CSF) pathway holds great potential in the treatment of inflammatory diseases. Mavrilimumab, a human monoclonal GM-CSF receptor-α antibody, has demonstrated clinical efficacy in RA. Our current study aimed to elucidate mechanisms of action and identify peripheral biomarkers associated with therapeutic responses of GM-CSF antagonism in RA. A 24-week placebo (PBO)-controlled trial was conducted in 305 RA patients who received mavrilimumab (30, 100 or 150 mg) or PBO once every 2 weeks. Serum biomarkers and whole blood gene expression profiles were measured by protein immunoassay and whole genome microarray. Mavrilimumab treatment induced significant down-regulation of type IV collagen formation marker (P4NP 7S), macrophage-derived chemokine (CCL22), IL-2 receptor α and IL-6 compared with PBO. Both early and sustained reduction of P4NP 7S was associated with clinical response to 150 mg mavrilimumab treatment. Gene expression analyses demonstrated reduced expression of transcripts enriched in macrophage and IL-22/IL-17 signalling pathways after GM-CSF blockade therapy. Myeloid and T cell-associated transcripts were suppressed in mavrilimumab-treated ACR20 responders but not non-responders. While CCL22 and IL-6 down-regulation may reflect a direct effect of GM-CSFR blockade on the production of pro-inflammatory mediators by myeloid cells, the suppression of IL-2 receptor α and IL-17/IL-22 associated transcripts suggests an indirect suppressive effect of mavrilimumab on T cell activation. Our results demonstrated association of peripheral biomarker changes with therapeutic response to mavrilimumab in RA patients. The sustained efficacy of mavrilimumab in RA may result from both direct effects on myeloid cells and indirect effects on T cell activation after GM-CSFR blockade.

  1. Dual blockade with candesartan cilexetil and lisinopril in hypertensive patients with diabetes mellitus

    DEFF Research Database (Denmark)

    Andersen, Niels H; Knudsen, Søren T; Poulsen, Per L


    BACKGROUND: Blood pressure (BP) reduction is the key to risk reduction of cardiovascular disease or renal failure in hypertensive patients with diabetes mellitus. Inhibition of the renin-angiotensin system by an angiotensin-converting enzyme (ACE) inhibitor or an angiotensin II receptor blocker...... (ARB) provides efficient BP reduction and renal protection in hypertensive diabetes patients. But, despite this, the recommended BP levels can be difficult to achieve and dual blockade therapy might be a possible way of obtaining efficient BP reduction in hypertensive patients with diabetes. Dual......, active-controlled, parallel-group study, investigating the efficacy and tolerability of candesartan cilexetil in combination with lisinopril, compared with the maximum recommended dose of lisinopril in hypertensive patients with diabetes mellitus. The study design consists of two treatment arms...

  2. Cyclosporine preserves the anergic state of human T cells induced by costimulation blockade in vitro.

    NARCIS (Netherlands)

    Koenen, H.J.P.M.; Fasse, E.; Joosten, I.


    BACKGROUND: Costimulation blockade based tolerance-inducing therapies might be disrupted by adjunct conventional immunosuppressive drug use. In the current study, we evaluated the compatibility of various immunosuppressive agents on costimulation blockade-based immunosuppression and T-cell anergy

  3. Rationale for an early aldosterone blockade in acute myocardial infarction and design of the ALBATROSS trial. (United States)

    Beygui, Farzin; Vicaut, Eric; Ecollan, Patrick; Machecourt, Jacques; Van Belle, Eric; Zannad, Faiez; Montalescot, Gilles


    Aldosterone is at its highest levels at presentation for acute myocardial infarction (AMI). High aldosterone levels are predictive of poor outcome regardless of heart failure. Angiotensin-converting enzyme inhibitors have delayed partial and temporary effects on aldosterone levels. We hypothesize that aldosterone receptor blockade, early after AMI onset on top of standard therapy, may improve clinical outcome. ALBATROSS is a nationwide, multicenter, open-labeled, randomized trial designed to assess the superiority of aldosterone blockade by a 200-mg intravenous bolus of potassium canrenoate followed by a daily 25-mg dose of spirinolactone for 6 months, on top of standard therapy compared to standard therapy alone among 1,600 patients admitted for ST-segment elevation or high risk non-ST-segment elevation acute AMI -TIMI score ≥3-within 72 hours after symptom onset regardless of heart failure and treatment strategy. The primary efficacy end point of the study is the 6-month rate of the composite of death, resuscitated cardiac arrest, significant ventricular arrhythmia, class IA American College of Cardiology/American Heart Association/European Society of Cardiology indication for implantable cardioverter device, and new or worsening heart failure. Secondary end points include each of the components of the primary end point, different combinations of such components, the primary end point assessed at hospital discharge and 30-day follow-up, and rates of acute renal failure. Safety end points include rates of hyperkalemia and premature drug discontinuation. ALBATROSS will assess the cardiovascular benefit of a low-cost aldosterone receptor blocker on top of standard therapy in all-coming AMI patients. Copyright © 2010 Mosby, Inc. All rights reserved.

  4. Angiotensin type 2 receptors: blood pressure regulation and end organ damage. (United States)

    Sumners, Colin; de Kloet, Annette D; Krause, Eric G; Unger, Thomas; Steckelings, Ulrike Muscha


    In most situations, the angiotensin AT2-receptor (AT2R) mediates physiological actions opposing those mediated by the AT1-receptor (AT1R), including a vasorelaxant effect. Nevertheless, experimental evidence vastly supports that systemic application of AT2R-agonists is blood pressure neutral. However, stimulation of AT2R locally within the brain or the kidney apparently elicits a systemic blood pressure lowering effect. A systemic effect of AT2R stimulation on blood pressure can also be achieved, when the prevailing effect of continuous background AT1R-stimulation is attenuated by low-dose AT1R blockade. Despite a lack of effect on blood pressure, AT2R stimulation still protects from hypertensive end-organ damage. Current data and evidence therefore suggest that AT2R agonists will not be suitable as future anti-hypertensive drugs, but that they may well be useful for end-organ protection in combination with established anti-hypertensives. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Entanglement of two ground state neutral atoms using Rydberg blockade

    DEFF Research Database (Denmark)

    Miroshnychenko, Yevhen; Browaeys, Antoine; Evellin, Charles


    We report on our recent progress in trapping and manipulation of internal states of single neutral rubidium atoms in optical tweezers. We demonstrate the creation of an entangled state between two ground state atoms trapped in separate tweezers using the effect of Rydberg blockade. The quality...... of the entanglement is measured using global rotations of the internal states of both atoms....

  6. Effect of Dual Blockade of Renin-Angiotensin Aldosterone System ...

    African Journals Online (AJOL)

    Purpose: To investigate the dual effect of angiotensin blockade by irbesartan and enalapril on proteinuria in diabetic patients with azotemia. Methods: Patients with diabetes of > 5 years duration, proteinuria at a nephrotic level and serum creatinine > 1.5 mg/dL were enrolled in the study. Forty-five enrolled patients were ...

  7. Combination Approaches with Immune-Checkpoint Blockade in Cancer Therapy

    NARCIS (Netherlands)

    Swart, M.; Verbrugge, I.; Beltman, J.B.


    In healthy individuals, immune-checkpoint molecules prevent autoimmune responses and limit immune cell-mediated tissue damage. Tumors frequently exploit these molecules to evade eradication by the immune system. Over the past years, immune-checkpoint blockade of cytotoxic T lymphocyte antigen-4 and

  8. Effective dermatomal blockade after subcostal transversus abdominis plane block

    DEFF Research Database (Denmark)

    Mitchell, Anja Ulrike; Torup, Henrik; Hansen, Egon G


    . Sensory assessment of a TAP block may guide the decision on the extent of the block. The purpose of this study was to investigate if the dermatomal extent of sensory blockade after injection of 20 ml 0.5% ropivacaine bilaterally into the TAP can be assessed using cold and pinprick sensation....

  9. Anisotropic Pauli spin blockade in hole quantum dots

    NARCIS (Netherlands)

    Brauns, M.; Ridderbos, Joost; Ridderbos, Joost; Li, Ang; Bakkers, Erik P.A.M.; van der Wiel, Wilfred Gerard; Zwanenburg, Floris Arnoud


    We present measurements on gate-defined double quantum dots in Ge-Si core-shell nanowires, which we tune to a regime with visible shell filling in both dots. We observe a Pauli spin blockade and can assign the measured leakage current at low magnetic fields to spin-flip cotunneling, for which we

  10. Coulomb blockade and superuniversality of the theta angle

    NARCIS (Netherlands)

    Burmistrov, I.S.; Pruisken, A.M.M.


    Based on the Ambegaokar-Eckern-Schön approach to the Coulomb blockade, we develop a complete quantum theory of the single electron transistor. We identify a previously unrecognized physical observable in the problem that, unlike the usual average charge on the island, is robustly quantized for any

  11. A mean field approach to Coulomb blockade for a disordered ...

    Indian Academy of Sciences (India)

    The Coulomb blockade (CB) in quantum dots (QDs) is by now well documented. It has been used to guide the fabrication of single electron transistors. Even the most sophisticated techniques for synthesizing QDs (e.g. MOCVD/MBE) result in an assembly in which a certain amount of disorder is inevitable. On the other hand, ...

  12. Benefits and harms of perioperative beta-blockade

    DEFF Research Database (Denmark)

    Wetterslev, Jørn; Juul, Anne Benedicte


    randomized trials. However, confidence intervals of the intervention effects in the meta-analyses are wide, leaving room for both benefits and harms. The largest observational study performed suggests that perioperative beta-blockade is associated with higher mortality in patients with low cardiac risk...

  13. Topological matter with collective encoding and Rydberg blockade

    DEFF Research Database (Denmark)

    Nielsen, Anne E. B.; Mølmer, Klaus


    We propose to use a permutation symmetric sample of multilevel atoms to simulate the properties of topologically ordered states. The Rydberg blockade interaction is used to prepare states of the sample which are equivalent to resonating valence bond states, Laughlin states, and string...

  14. Is deep neuromuscular blockade beneficial in laparoscopic surgery?

    DEFF Research Database (Denmark)

    Madsen, M. V.; Staehr-Rye, A K; Claudius, C


    this in narrative form. We have shared our analysis and text with the authors of the 'Con-' side of these paired position papers during the preparation of the manuscripts. RESULTS: There are a few low risk of bias studies indicating that use of deep neuromuscular blockade improve surgical conditions and improve...

  15. Deterioration of kidney function by the (pro)renin receptor blocker handle region peptide in aliskiren-treated diabetic transgenic (mRen2)27 rats

    NARCIS (Netherlands)

    L. te Riet (Luuk); M.M. van den Heuvel (Mieke); C.J. Peutz-Kootstra (Carine); J.H.M. Esch, van (Joep); R. van Veghel (Richard); I.M. Garrelds (Ingrid); U. Musterd-Bhaggoe (Usha); A.M.B. Bouhuizen (Angelique); F.P.J. Leijten (Frank); A.H.J. Danser (Jan); W.W. Batenburg (Wendy)


    textabstractDual renin-angiotensin system (RAS) blockade in diabetic nephropathy is no longer feasible because of the profit/side effect imbalance. (Pro)renin receptor [(P)RR] blockade with handle region peptide (HRP) has been reported to exert beneficial effects in various diabetic models in a

  16. A bioluminescence resonance energy transfer 2 (BRET2) assay for monitoring seven transmembrane receptor and insulin receptor crosstalk

    DEFF Research Database (Denmark)

    Sanni, Samra Joke; Kulahin, Nikolaj; Jorgensen, Rasmus


    The angiotensin AT1 receptor is a seven transmembrane (7TM) receptor, which mediates the regulation of blood pressure. Activation of angiotensin AT1 receptor may lead to impaired insulin signaling indicating crosstalk between angiotensin AT1 receptor and insulin receptor signaling pathways. To el...

  17. BU08073 a buprenorphine analogue with partial agonist activity at μ-receptors in vitro but long-lasting opioid antagonist activity in vivo in mice. (United States)

    Khroyan, T V; Wu, J; Polgar, W E; Cami-Kobeci, G; Fotaki, N; Husbands, S M; Toll, L


    Buprenorphine is a potent analgesic with high affinity at μ, δ and κ and moderate affinity at nociceptin opioid (NOP) receptors. Nevertheless, NOP receptor activation modulates the in vivo activity of buprenorphine. Structure activity studies were conducted to design buprenorphine analogues with high affinity at each of these receptors and to characterize them in in vitro and in vivo assays. Compounds were tested for binding affinity and functional activity using [(35) S]GTPγS binding at each receptor and a whole-cell fluorescent assay at μ receptors. BU08073 was evaluated for antinociceptive agonist and antagonist activity and for its effects on anxiety in mice. BU08073 bound with high affinity to all opioid receptors. It had virtually no efficacy at δ, κ and NOP receptors, whereas at μ receptors, BU08073 has similar efficacy as buprenorphine in both functional assays. Alone, BU08073 has anxiogenic activity and produces very little antinociception. However, BU08073 blocks morphine and U50,488-mediated antinociception. This blockade was not evident at 1 h post-treatment, but is present at 6 h and remains for up to 3-6 days. These studies provide structural requirements for synthesis of 'universal' opioid ligands. BU08073 had high affinity for all the opioid receptors, with moderate efficacy at μ receptors and reduced efficacy at NOP receptors, a profile suggesting potential analgesic activity. However, in vivo, BU08073 had long-lasting antagonist activity, indicating that its pharmacokinetics determined both the time course of its effects and what receptor-mediated effects were observed. This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles in this section visit © 2014 The British Pharmacological Society.

  18. N-cadherin and integrin blockade inhibit arteriolar myogenic reactivity but not pressure-induced increases in intracellular Ca2+

    Directory of Open Access Journals (Sweden)

    Teresa Y. Jackson


    Full Text Available The vascular myogenic response is characterized by arterial constriction in response to an increase in intraluminal pressure and dilatation to a decrease in pressure. This mechanism is important for the regulation of blood flow, capillary pressure and arterial pressure. The identity of the mechanosensory mechanism(s for this response is incompletely understood but has been shown to include the integrins as cell-extracellular matrix receptors. The possibility that a cell-cell adhesion receptor is involved has not been studied. Thus, we tested the hypothesis that N-cadherin, a cell-cell adhesion molecule in vascular smooth muscle cells (VSMCs, was important for myogenic responsiveness. The purpose of this study was to investigate:
    1. whether cadherin inhibition blocks myogenic responses to increases in intraluminal pressure and 2. the effect of the cadherin or integrin blockade on pressure-induced changes in [Ca2+]i. Cadherin blockade was tested in isolated rat cremaster arterioles on myogenic responses to acute pressure steps from 60 – 100 mmHg and changes in VSMC Ca2+ were measured using fura-2. In the presence of a synthetic cadherin inhibitory peptide or a function blocking antibody, myogenic responses were inhibited. In contrast, during N-cadherin blockade, pressure-induced changes in [Ca2+]i were not altered. Similarly, vessels treated with function-blocking β1- or β3-integrin antibodies maintained pressure-induced [Ca2+]i responses despite inhibition of myogenic constriction. Collectively, these data suggest that both cadherins and integrins play a fundamental role in mediating myogenic constriction but argue against their direct involvement in mediating pressure-induced [Ca2+]i increases.

  19. Lack of evidence for AT1R/B2R heterodimerization in COS-7, HEK293, and NIH3T3 cells: how common is the AT1R/B2R heterodimer?

    DEFF Research Database (Denmark)

    Hansen, Jakob L; Hansen, Jonas T; Speerschneider, Tobias


    It has been suggested previously ( AbdAlla, S., Lother, H., and Quitterer, U. (2000) Nature 407, 94-98 ) that the angiotensin II type 1 receptor (AT1R) and the bradykinin B2 receptor (B2R) form constitutive heterodimers. Furthermore they demonstrate that AT1R signaling significantly increases in ...

  20. Conductance of a proximitized nanowire in the Coulomb blockade regime (United States)

    van Heck, B.; Lutchyn, R. M.; Glazman, L. I.


    We identify the leading processes of electron transport across finite-length segments of proximitized nanowires and build a quantitative theory of their two-terminal conductance. In the presence of spin-orbit interaction, a nanowire can be tuned across the topological transition point by an applied magnetic field. Due to a finite segment length, electron transport is controlled by the Coulomb blockade. Upon increasing of the field, the shape and magnitude of the Coulomb blockade peaks in the linear conductance are defined, respectively, by Andreev reflection, single-electron tunneling, and resonant tunneling through the Majorana modes emerging after the topological transition. Our theory provides the framework for the analysis of experiments with proximitized nanowires [such as reported in S. M. Albrecht et al., Nature (London) 531, 206 (2016), 10.1038/nature17162] and identifies the signatures of the topological transition in the two-terminal conductance.

  1. Single-photon source based on Rydberg exciton blockade (United States)

    Khazali, Mohammadsadegh; Heshami, Khabat; Simon, Christoph


    Bound states of electron–hole pairs in semiconductors demonstrate a hydrogen-like behavior in their high-lying excited states that are also known as Rydberg exciton states. The strong interaction between excitons in levels with high principal quantum numbers prevents the creation of more than one exciton in a small crystal; resulting in the Rydberg blockade effect. Here, we propose a new kind of solid-state single-photon source based on the recently observed Rydberg blockade effect for excitons in cuprous oxide. Our quantitative estimates based on single and double excitation probability dynamics indicate that GHz rates and values of the second-order correlation function {g}2(0) below the percent level can be simultaneously achievable. These results should pave the way to explore applications of Rydberg excitons in photonic quantum information processing.

  2. Cardioprotection conferred by exercise training is blunted by blockade of the opioid system

    Directory of Open Access Journals (Sweden)

    Tatiana F. G Galvão


    Full Text Available OBJECTIVES: To investigate the effect of opioid receptor blockade on the myocardial protection conferred by chronic exercise and to compare exercise training with different strategies of myocardial protection (opioid infusion and brief periods of ischemia-reperfusion preceding irreversible left anterior descending coronary ligation. INTRODUCTION: The acute cardioprotective effects of exercise training are at least partly mediated through opioid receptor-dependent mechanisms in ischemia-reperfusion models. METHODS: Male Wistar rats (n = 76 were randomly assigned to 7 groups: (1 control; (2 exercise training; (3 morphine; (4 intermittent ischemia-reperfusion (three alternating periods of left anterior descending coronary occlusion and reperfusion; (5 exercise training+morphine; (6 naloxone (a non-selective opioid receptor blocker plus morphine; (7 naloxone before each exercise-training session. Myocardial infarction was established in all groups by left anterior descending coronary ligation. Exercise training was performed on a treadmill for 60 minutes, 5 times/week, for 12 weeks, at 60% peak oxygen (peak VO2. Infarct size was histologically evaluated. RESULTS: Exercise training significantly increased exercise capacity and ΔVO2 (VO2 peak - VO2 rest (p<0.01 vs. sedentary groups. Compared with control, all treatment groups except morphine plus naloxone and exercise training plus naloxone showed a smaller infarcted area (p<0.05. No additional decrease in infarct size occurred in the exercise training plus morphine group. No difference in myocardial capillary density (p = 0.88 was observed in any group. CONCLUSIONS: Exercise training, morphine, exercise training plus morphine and ischemia-reperfusion groups had a smaller infarcted area than the control group. The effect of chronic exercise training in decreasing infarct size seems to occur, at least in part, through the opioid receptor stimulus and not by increasing myocardial perfusion

  3. Assessing the translational feasibility of pharmacological drug memory reconsolidation blockade with memantine in quitting smokers. (United States)

    Das, Ravi K; Hindocha, Chandni; Freeman, Tom P; Lazzarino, Antonio I; Curran, H Valerie; Kamboj, Sunjeev K


    Preclinical reconsolidation research offers the first realistic opportunity to pharmacologically weaken the maladaptive memory structures that support relapse in drug addicts. N-methyl D-aspartate receptor (NMDAR) antagonism is a highly effective means of blocking drug memory reconsolidation. However, no research using this approach exists in human addicts. The objective of this study was to assess the potential and clinical outcomes of blocking the reconsolidation of cue-smoking memories with memantine in quitting smokers. Fifty-nine dependent and motivated to quit smokers were randomised to one of three groups receiving the following: (1) memantine with or (2) without reactivation of associative cue-smoking memories or (3) reactivation with placebo on their target quit day in a double-blind manner. Participants aimed to abstain from smoking for as long as possible. Levels of smoking and FTND score were assessed prior to intervention and up to a year later. Primary outcome was latency to relapse. Subjective craving measures and attentional bias to smoking cues were assessed in-lab. All study groups successfully reduced their smoking up to 3 months. Memantine in combination with smoking memory reactivation did not affect any measure of smoking outcome, reactivity or attention capture to smoking cues. Brief exposure to smoking cues with memantine did not appear to weaken these memory traces. These findings could be due to insufficient reconsolidation blockade by memantine or failure of exposure to smoking stimuli to destabilise smoking memories. Research assessing the treatment potential of reconsolidation blockade in human addicts should focus on identification of tolerable drugs that reliably block reward memory reconsolidation and retrieval procedures that reliably destabilise strongly trained memories.

  4. Blockade of immunosuppressive cytokines restores NK cell antiviral function in chronic hepatitis B virus infection.

    Directory of Open Access Journals (Sweden)

    Dimitra Peppa


    Full Text Available NK cells are enriched in the liver, constituting around a third of intrahepatic lymphocytes. We have previously demonstrated that they upregulate the death ligand TRAIL in patients with chronic hepatitis B virus infection (CHB, allowing them to kill hepatocytes bearing TRAIL receptors. In this study we investigated whether, in addition to their pathogenic role, NK cells have antiviral potential in CHB. We characterised NK cell subsets and effector function in 64 patients with CHB compared to 31 healthy controls. We found that, in contrast to their upregulated TRAIL expression and maintenance of cytolytic function, NK cells had a markedly impaired capacity to produce IFN-γ in CHB. This functional dichotomy of NK cells could be recapitulated in vitro by exposure to the immunosuppressive cytokine IL-10, which was induced in patients with active CHB. IL-10 selectively suppressed NK cell IFN-γ production without altering cytotoxicity or death ligand expression. Potent antiviral therapy reduced TRAIL-expressing CD56(bright NK cells, consistent with the reduction in liver inflammation it induced; however, it was not able to normalise IL-10 levels or the capacity of NK cells to produce the antiviral cytokine IFN-γ. Blockade of IL-10 +/- TGF-β restored the capacity of NK cells from both the periphery and liver of patients with CHB to produce IFN-γ, thereby enhancing their non-cytolytic antiviral capacity. In conclusion, NK cells may be driven to a state of partial functional tolerance by the immunosuppressive cytokine environment in CHB. Their defective capacity to produce the antiviral cytokine IFN-γ persists in patients on antiviral therapy but can be corrected in vitro by IL-10+/- TGF-β blockade.

  5. Pathophysiology and Etiology of Nerve Injury Following Peripheral Nerve Blockade. (United States)

    Brull, Richard; Hadzic, Admir; Reina, Miguel A; Barrington, Michael J


    This review synthesizes anatomical, anesthetic, surgical, and patient factors that may contribute to neurologic complications associated with peripheral nerve blockade. Peripheral nerves have anatomical features unique to a given location that may influence risk of injury. Peripheral nerve blockade-related peripheral nerve injury (PNI) is most severe with intrafascicular injection. Surgery and its associated requirements such as positioning and tourniquet have specific risks. Patients with preexisting neuropathy may be at an increased risk of postoperative neurologic dysfunction. Distinguishing potential causes of PNI require clinical assessment and investigation; a definitive diagnosis, however, is not always possible. Fortunately, most postoperative neurologic dysfunction appears to resolve with time, and the incidence of serious long-term nerve injury directly attributable to peripheral nerve blockade is relatively uncommon. Nonetheless, despite the use of ultrasound guidance, the risk of block-related PNI remains unchanged. Since the 2008 Practice Advisory, new information has been published, furthering our understanding of the microanatomy of peripheral nerves, mechanisms of peripheral nerve injection injury, toxicity of local anesthetics, the etiology of and monitoring methods, and technologies that may decrease the risk of nerve block-related peripheral nerve injury.

  6. Neuromuscular blockade in cardiac surgery: An update for clinicians

    Directory of Open Access Journals (Sweden)

    Hemmerling Thomas


    Full Text Available There have been great advancements in cardiac surgery over the last two decades; the widespread use of off-pump aortocoronary bypass surgery, minimally invasive cardiac surgery, and robotic surgery have also changed the face of cardiac anaesthesia. The concept of "Fast-track anaesthesia" demands the use of nondepolarising neuromuscular blocking drugs with short duration of action, combining the ability to provide (if necessary sufficiently profound neuromuscular blockade during surgery and immediate re-establishment of normal neuromuscular transmission at the end of surgery. Postoperative residual muscle paralysis is one of the major hurdles for immediate or early extubation after cardiac surgery. Nondepolarising neuromuscular blocking drugs for cardiac surgery should therefore be easy to titrate, of rapid onset and short duration of action with a pathway of elimination independent from hepatic or renal dysfunction, and should equally not affect haemodynamic stability. The difference between repetitive bolus application and continuous infusion is outlined in this review, with the pharmacodynamic and pharmacokinetic characteristics of vecuronium, pancuronium, rocuronium, and cisatracurium. Kinemyography and acceleromyography are the most important currently used neuromuscular monitoring methods. Whereas monitoring at the adductor pollicis muscle is appropriate at the end of surgery, monitoring of the corrugator supercilii muscle better reflects neuromuscular blockade at more central, profound muscles, such as the diaphragm, larynx, or thoraco-abdominal muscles. In conclusion, cisatracurium or rocuronium is recommended for neuromuscular blockade in modern cardiac surgery.

  7. Mismatch Repair Deficiency and Response to Immune Checkpoint Blockade (United States)

    Lee, Valerie; Murphy, Adrian; Le, Dung T.


    More than 1.6 million new cases of cancer will be diagnosed in the U.S. in 2016, resulting in more than 500,000 deaths. Although chemotherapy has been the mainstay of treatment in advanced cancers, immunotherapy development, particularly with PD-1 inhibitors, has changed the face of treatment for a number of tumor types. One example is the subset of tumors characterized by mismatch repair deficiency and microsatellite instability that are highly sensitive to PD-1 blockade. Hereditary forms of cancer have been noted for more than a century, but the molecular changes underlying mismatch repair-deficient tumors and subsequent microsatellite unstable tumors was not known until the early 1990s. In this review article, we discuss the history and pathophysiology of mismatch repair, the process of testing for mismatch repair deficiency and microsatellite instability, and the role of immunotherapy in this subset of cancers. Implications for Practice: Mismatch repair deficiency has contributed to our understanding of carcinogenesis for the past 2 decades and now identifies a subgroup of traditionally chemotherapy-insensitive solid tumors as sensitive to PD-1 blockade. This article seeks to educate oncologists regarding the nature of mismatch repair deficiency, its impact in multiple tumor types, and its implications for predicting the responsiveness of solid tumors to immune checkpoint blockade. PMID:27412392

  8. Blockade of extracellular NM23 or its endothelial target slows breast cancer growth and metastasis. (United States)

    Yokdang, Nucharee; Nordmeier, Senny; Speirs, Katie; Burkin, Heather R; Buxton, Iain L O

    Nucleoside Diphosphate Kinase (NDPK), described as NM23 a metastasis suppressor, is found in the culture medium of cancer cells lines suggesting that the kinase may have an extracellular role. We propose that extracellular NM23 released from breast cancers in vivo stimulates tumor cell migration, proliferation and endothelial cell angiogenesis in support of metastasis development. NM23 in the bloodstream of immunocompromised mice carrying human triple-negative breast cancers or in breast cancer patients was measured by ELISA. Primary and metastatic tumor development, the impact of blockade of NM23 and/or its stimulation of nucleotide receptors were measured using in vivo imaging. NM23 expression data in the Curtis breast dataset was examined to test our hypothesis that NM23 may play a mechanistic role in breast cancer development. SCID mice carrying metastatic MDA-MB-231Luc+ triple-negative human breast tumor cells elaborate NM23 into the circulation correlated with primary tumor growth. Treatment of mice with the NM23 inhibitor ellagic acid (EA) or the purinergic receptor antagonist MRS2179 slowed primary tumor growth. At 16 weeks following implantation, lung metastases were reduced in mice treated with EA, MRS2179 or the combination. Expression of NM23 in the Curtis breast dataset confirmed a likely role for NM23 in tumor metastasis. Extracellular NM23 may constitute both a biomarker and a therapeutic target in the management of breast cancer.

  9. 2B4 (CD244) induced by selective CD28 blockade functionally regulates allograft-specific CD8+ T cell responses (United States)

    Liu, Danya; Krummey, Scott M.; Badell, I. Raul; Wagener, Maylene; Schneeweis, Lumelle A.; Stetsko, Dawn K.; Suchard, Suzanne J.; Nadler, Steven G.


    Mounting evidence in models of both autoimmunity and chronic viral infection suggests that the outcome of T cell activation is critically impacted by the constellation of co-stimulatory and co-inhibitory receptors expressed on the cell surface. Here, we identified a critical role for the co-inhibitory SLAM family member 2B4 (CD244) in attenuating primary antigen-specific CD8+ T cell responses in the presence of immune modulation with selective CD28 blockade. Our results reveal a specific up-regulation of 2B4 on antigen-specific CD8+ T cells in animals in which CD28 signaling was blocked. However, 2B4 up-regulation was not observed in animals treated with CTLA-4 Ig (abatacept) or CD28 blockade in the presence of anti–CTLA-4 mAb. 2B4 up-regulation after CD28 blockade was functionally significant, as the inhibitory impact of CD28 blockade was diminished when antigen-specific CD8+ T cells were deficient in 2B4. In contrast, 2B4 deficiency had no effect on CD8+ T cell responses during unmodified rejection or in the presence of CTLA-4 Ig. We conclude that blockade of CD28 signals in the presence of preserved CTLA-4 signals results in the unique up-regulation of 2B4 on primary CD8+ effectors, and that this 2B4 expression plays a critical functional role in controlling antigen-specific CD8+ T cell responses. PMID:24493803

  10. Vitamin D receptor activator and dietary sodium restriction to reduce residual urinary albumin excretion in chronic kidney disease (ViRTUE study) : rationale and study protocol

    NARCIS (Netherlands)

    Keyzer, Charlotte A.; de Jong, Maarten A.; van Breda, G. Fenna; Vervloet, Marc G.; Laverman, Gozewijn D.; Hemmelder, Marc; Janssen, Wilbert M.; Heerspink, Hiddo J. Lambers; Navis, Gerjan; de Borst, Martin H.

    Optimal albuminuria reduction is considered essential to halting chronic kidney disease (CKD) progression. Both vitamin D receptor activator (VDRA) treatment and dietary sodium restriction potentiate the efficacy of renin-angiotensin-aldosterone- system (RAAS) blockade to reduce albuminuria. The

  11. Human CB1 Receptor Isoforms, present in Hepatocytes and ?-cells, are Involved in Regulating Metabolism


    Isabel González-Mariscal; Krzysik-Walker, Susan M.; Doyle, Máire E; Qing-Rong Liu; Raffaello Cimbro; Sara Santa-Cruz Calvo; Soumita Ghosh; Łukasz Cieśla; Ruin Moaddel; Carlson, Olga D.; Witek, Rafal P.; Jennifer F. O’Connell; Josephine M Egan


    Therapeutics aimed at blocking the cannabinoid 1 (CB1) receptor for treatment of obesity resulted in significant improvements in liver function, glucose uptake and pancreatic ?-cell function independent of weight loss or CB1 receptor blockade in the brain, suggesting that peripherally-acting only CB1 receptor blockers may be useful therapeutic agents. Neuropsychiatric side effects and lack of tissue specificity precluded clinical use of first-generation, centrally acting CB1 receptor blockers...

  12. Synovial tissue rank ligand expression and radiographic progression in rheumatoid arthritis: observations from a proof-of-concept randomized clinical trial of cytokine blockade.

    LENUS (Irish Health Repository)

    Rooney, Terence


    The objective of the study was to evaluate synovial tissue receptor activator of nuclear factor-kappabeta ligand (RANKL) and osteoprotegerin (OPG) as biomarkers of disease activity, progressive joint damage, and therapeutic response, during cytokine blockade in rheumatoid arthritis (RA). Patients with active RA entered a randomized open-label 12-month study of anakinra 100 mg\\/day, administered as monotherapy or in combination with pegsunercept 800 mug\\/kg twice weekly. Arthroscopic synovial tissue biopsies were obtained at baseline, at 4 weeks and at the final time point. Following immunohistochemical staining, RANKL and OPG expression was quantified using digital image analysis. Radiographic damage was evaluated using the van der Heijde modification of the Sharp scoring system. Twenty-two patients were randomized. Baseline expression of RANKL, but not OPG, correlated significantly with baseline CRP levels (r = 0.61, P < 0.01). While a significant reduction in OPG expression following treatment was observed in clinical responders at the final time point (P < 0.05 vs. baseline), RANKL levels did not change, and the RANKL:OPG ratio remained unaltered, even at the highest levels of clinical response. When potential predictors of radiographic outcome were evaluated, baseline RANKL expression correlated with erosive progression at 1 year (r = 0.71, P < 0.01). Distinct, though related, pathophysiologic processes mediate joint inflammation and destruction in RA. Elevated synovial tissue RANKL expression is associated with progressive joint erosion, and may be independent of the clinical response to targeted therapy. The potential therapeutic importance of modulating RANKL in RA is highlighted, if radiographic arrest is to be achieved.

  13. Upregulation of ERK1/2-eNOS via AT2 receptors decreases the contractile response to angiotensin II in resistance mesenteric arteries from obese rats.

    Directory of Open Access Journals (Sweden)

    Graziela N Hagihara

    Full Text Available It has been clearly established that mitogen-activated protein kinases (MAPKS are important mediators of angiotensin II (Ang II signaling via AT1 receptors in the vasculature. However, evidence for a role of these kinases in changes of Ang II-induced vasoconstriction in obesity is still lacking. Here we sought to determine whether vascular MAPKs are differentially activated by Ang II in obese animals. The role of AT2 receptors was also evaluated. Male monosodium glutamate-induced obese (obese and non-obese Wistar rats (control were used. The circulating concentrations of Ang I and Ang II, determined by HPLC, were increased in obese rats. Ang II-induced isometric contraction was decreased in endothelium-intact resistance mesenteric arteries from obese compared with control rats and exhibited a retarded AT1 receptor antagonist response. Blocking of AT2 receptors and inhibition of either endothelial nitric oxide synthase (eNOS or extracellular signal-regulated protein kinases 1 and 2 (ERK1/2 restored Ang II-induced contraction in obese rats. Western blot analysis revealed increased protein expression of AT2 receptors in arteries from obese rats. Basal and Ang II-induced ERK1/2 phosphorylation was also increased in obese rats. Blockade of either AT1 or AT2 receptors corrected the increased ERK1/2 phosphorylation in arteries from obese rats to levels observed in control preparations. Phosphorylation of eNOS was increased in obese rats. Incubation with the ERK1/2 inhibitor before Ang II stimulation did not affect eNOS phosphorylation in control rats; however, it corrected the increased phosphorylation of eNOS in obese rats. These results clearly demonstrate that enhanced AT2 receptor and ERK1/2-induced, NO-mediated vasodilation reduces Ang II-induced contraction in an endothelium-dependent manner in obese rats.

  14. Upregulation of ERK1/2-eNOS via AT2 receptors decreases the contractile response to angiotensin II in resistance mesenteric arteries from obese rats. (United States)

    Hagihara, Graziela N; Lobato, Nubia S; Filgueira, Fernando P; Akamine, Eliana H; Aragão, Danielle S; Casarini, Dulce E; Carvalho, Maria Helena C; Fortes, Zuleica B


    It has been clearly established that mitogen-activated protein kinases (MAPKS) are important mediators of angiotensin II (Ang II) signaling via AT1 receptors in the vasculature. However, evidence for a role of these kinases in changes of Ang II-induced vasoconstriction in obesity is still lacking. Here we sought to determine whether vascular MAPKs are differentially activated by Ang II in obese animals. The role of AT2 receptors was also evaluated. Male monosodium glutamate-induced obese (obese) and non-obese Wistar rats (control) were used. The circulating concentrations of Ang I and Ang II, determined by HPLC, were increased in obese rats. Ang II-induced isometric contraction was decreased in endothelium-intact resistance mesenteric arteries from obese compared with control rats and exhibited a retarded AT1 receptor antagonist response. Blocking of AT2 receptors and inhibition of either endothelial nitric oxide synthase (eNOS) or extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) restored Ang II-induced contraction in obese rats. Western blot analysis revealed increased protein expression of AT2 receptors in arteries from obese rats. Basal and Ang II-induced ERK1/2 phosphorylation was also increased in obese rats. Blockade of either AT1 or AT2 receptors corrected the increased ERK1/2 phosphorylation in arteries from obese rats to levels observed in control preparations. Phosphorylation of eNOS was increased in obese rats. Incubation with the ERK1/2 inhibitor before Ang II stimulation did not affect eNOS phosphorylation in control rats; however, it corrected the increased phosphorylation of eNOS in obese rats. These results clearly demonstrate that enhanced AT2 receptor and ERK1/2-induced, NO-mediated vasodilation reduces Ang II-induced contraction in an endothelium-dependent manner in obese rats.

  15. Brief treatment with the glucocorticoid receptor antagonist mifepristone normalizes the reduction in neurogenesis after chronic stress.

    NARCIS (Netherlands)

    Oomen, C.A.; Mayer, J.L.; de Kloet, E.R.; Joëls, M.; Lucassen, P.J.


    In rodents, stress suppresses adult neurogenesis. This is thought to involve activation of glucocorticoid receptors in the brain. In the present study, we therefore questioned whether glucocorticoid receptor blockade by mifepristone can normalize the effects of chronic stress on adult neurogenesis.

  16. Serotonin 2A receptor antagonists for treatment of schizophrenia

    DEFF Research Database (Denmark)

    Ebdrup, Bjørn Hylsebeck; Rasmussen, Hans; Arnt, Jørn


    : Preclinical, clinical and post-mortem studies of the serotonin 5-HT2A system in schizophrenia are reviewed. The implications of a combined D2 and 5-HT2A receptor blockade, which is obtained by several current antipsychotic drugs, are discussed, and the rationale for the development of more selective 5-HT2A...

  17. Dual ETA/ETB blockade with macitentan improves both vascular remodeling and angiogenesis in pulmonary arterial hypertension (United States)

    Nadeau, Valerie; Potus, Francois; Boucherat, Olivier; Paradis, Renee; Tremblay, Eve; Iglarz, Marc; Paulin, Roxane; Bonnet, Sebastien


    Dysregulated metabolism and rarefaction of the capillary network play a critical role in pulmonary arterial hypertension (PAH) etiology. They are associated with a decrease in perfusion of the lungs, skeletal muscles, and right ventricle (RV). Previous studies suggested that endothelin-1 (ET-1) modulates both metabolism and angiogenesis. We hypothesized that dual ETA/ETB receptors blockade improves PAH by improving cell metabolism and promoting angiogenesis. Five weeks after disease induction, Sugen/hypoxic rats presented severe PAH with pulmonary artery (PA) remodeling, RV hypertrophy and capillary rarefaction in the lungs, RV, and skeletal muscles (microCT angiogram, lectin perfusion, CD31 staining). Two-week treatment with dual ETA/ETB receptors antagonist macitentan (30 mg/kg/d) significantly improved pulmonary hemodynamics, PA vascular remodeling, and RV function and hypertrophy compared to vehicle-treated animals (all P = 0.05). Moreover, macitentan markedly increased lung, RV and quadriceps perfusion, and microvascular density (all P = 0.05). In vitro, these effects were associated with increases in oxidative phosphorylation (oxPhox) and markedly reduced cell proliferation of PAH-PA smooth muscle cells (PASMCs) treated with macitentan without affecting apoptosis. While macitentan did not affect oxPhox, proliferation, and apoptosis of PAH–PA endothelial cells (PAECs), it significantly improved their angiogenic capacity (tube formation assay). Exposure of control PASMC and PAEC to ET-1 fully mimicked the PAH cells phenotype, thus confirming that ET-1 is implicated in both metabolism and angiogenesis abnormalities in PAH. Dual ETA/ETB receptor blockade improved the metabolic changes involved in PAH-PASMCs’ proliferation and the angiogenic capacity of PAH-PAEC leading to an increased capillary density in lungs, RV, and skeletal muscles. PMID:29064353

  18. Particle conformation regulates antibody access to a conserved GII.4 norovirus blockade epitope. (United States)

    Lindesmith, Lisa C; Donaldson, Eric F; Beltramello, Martina; Pintus, Stefania; Corti, Davide; Swanstrom, Jesica; Debbink, Kari; Jones, Taylor A; Lanzavecchia, Antonio; Baric, Ralph S


    GII.4 noroviruses (NoVs) are the primary cause of epidemic viral acute gastroenteritis. One primary obstacle to successful NoV vaccination is the extensive degree of antigenic diversity among strains. The major capsid protein of GII.4 strains is evolving rapidly, resulting in the emergence of new strains with altered blockade epitopes. In addition to characterizing these evolving blockade epitopes, we have identified monoclonal antibodies (MAbs) that recognize a blockade epitope conserved across time-ordered GII.4 strains. Uniquely, the blockade potencies of MAbs that recognize the conserved GII.4 blockade epitope were temperature sensitive, suggesting that particle conformation may regulate functional access to conserved blockade non-surface-exposed epitopes. To map conformation-regulating motifs, we used bioinformatics tools to predict conserved motifs within the protruding domain of the capsid and designed mutant VLPs to test the impacts of substitutions in these motifs on antibody cross-GII.4 blockade. Charge substitutions at residues 310, 316, 484, and 493 impacted the blockade potential of cross-GII.4 blockade MAbs with minimal impact on the blockade of MAbs targeting other, separately evolving blockade epitopes. Specifically, residue 310 modulated antibody blockade temperature sensitivity in the tested strains. These data suggest access to the conserved GII.4 blockade antibody epitope is regulated by particle conformation, temperature, and amino acid residues positioned outside the antibody binding site. The regulating motif is under limited selective pressure by the host immune response and may provide a robust target for broadly reactive NoV therapeutics and protective vaccines. In this study, we explored the factors that govern norovirus (NoV) cross-strain antibody blockade. We found that access to the conserved GII.4 blockade epitope is regulated by temperature and distal residues outside the antibody binding site. These data are most consistent with a

  19. Effect of epidural blockade and oxygen therapy on changes in subcutaneous oxygen tension after abdominal surgery

    DEFF Research Database (Denmark)

    Rosenberg, J; Pedersen, U; Erichsen, C J


    The effect of oxygen therapy (37% by face mask) and epidural local anesthetic blockade (9 ml 0.5% bupivacaine at Th9-11 level) on wound oxygenation was evaluated in eight otherwise healthy patients undergoing elective colorectal resection. The patients were monitored continuously for subcutaneous...... any of the measured values. Oxygen therapy before epidural blockade increased median subcutaneous oxygen tension from 60 to 71 mmHg (P oxygen tension with oxygen therapy was 30 (15-55) min...... without epidural blockade and 15 (10-20) min with blockade (P oxygen tension with or without oxygen therapy after elective uncomplicated major abdominal surgery....

  20. Autonomic Blockade Reverses Endothelial Dysfunction in Obesity-Associated Hypertension. (United States)

    Gamboa, Alfredo; Figueroa, Rocío; Paranjape, Sachin Y; Farley, Ginnie; Diedrich, Andre; Biaggioni, Italo


    Impaired nitric oxide (NO) vasodilation (endothelial dysfunction) is associated with obesity and thought to be a factor in the development of hypertension. We previously found that NO synthesis inhibition had similar pressor effects in obese hypertensives compared with healthy control during autonomic blockade, suggesting that impaired NO vasodilation is secondary to sympathetic activation. We tested this hypothesis by determining the effect of autonomic blockade (trimethaphan 4 mg/min IV) on NO-mediated vasodilation (increase in forearm blood flow to intrabrachial acetylcholine) compared with endothelial-independent vasodilation (intrabrachial sodium nitroprusside) in obese hypertensive subjects (30obese subjects (49±3.6 years, 34±1 kg/m(2), 165/94±7/6 mm Hg), on separate occasions 1 month apart, randomly assigned. Autonomic blockade increased basal forearm blood flow (from 3.9±0.7 to 5.2±1.2 mL/100 mL per minute, P=0.078). As expected, NO-mediated vasodilation was blunted on the intact day compared with NO-independent vasodilation; forearm blood flow increased from 3.6±0.6 to 10.1±1.1 with the highest dose of nitroprusside, but only from 3.7±0.4 to 7.2±0.8 mL/100 mL per minute with the highest dose of acetylcholine, Pobesity-associated hypertension and provides further rationale to explore it as a therapeutic target. © 2016 American Heart Association, Inc.

  1. Precipitated withdrawal during maintenance opioid blockade with extended release naltrexone. (United States)

    Fishman, Marc


    Background There has been increasing interest in the use of extended release injectable naltrexone for the treatment of opioid dependence. Case description We report a case of precipitated withdrawal in a 17-year-old adolescent female receiving extended release naltrexone (Vivitrol) for opioid dependence, following her third serial monthly dose of the medication, several days after using oxycodone with mild intoxication. Conclusions This case suggests that, in some circumstances, the opioid blockade may be overcome when naltrexone levels drop towards the end of the dosing interval, producing vulnerability to subsequent naltrexone-induced withdrawal. This may provide cautionary guidance for clinical management and dosing strategies.

  2. Neural Blockade for Persistent Pain After Breast Cancer Surgery

    DEFF Research Database (Denmark)

    Wijayasinghe, Nelun; Andersen, Kenneth Geving; Kehlet, Henrik


    involved in neuropathic pain syndromes or to be used as a treatment in its own right. The purpose of this review was to examine the evidence for neural blockade as a potential diagnostic tool or treatment for persistent pain after breast cancer surgery. In this systematic review, we found only 7 studies (n...... = 135) assessing blocks directed at 3 neural structures-stellate ganglion, paravertebral plexus, and intercostal nerves-but none focusing on the intercostobrachial nerve. The quality of the studies was low and efficacy inconclusive, suggesting a need for well-designed, high-quality studies...

  3. Uncoupling of the baroreflex by N(N)-cholinergic blockade in dissecting the components of cardiovascular regulation (United States)

    Shannon, J. R.; Jordan, J.; Black, B. K.; Costa, F.; Robertson, D.


    Systemic administration of adrenergic agonists and nitric oxide donors is used extensively to determine cardiovascular receptor sensitivity. Conclusions regarding receptor sensitivity in the presence of the baroreflex may be misleading. In 8 normal volunteers, we determined the heart rate and blood pressure changes after incremental bolus doses of isoproterenol, phenylephrine, and sodium nitroprusside before and during neuronal nicotinic cholinergic (N(N)-cholinergic) blockade with trimethaphan. Results are given as median (25th/75th percentile). With trimethaphan, the baroreflex slope (as determined by bolus doses of nitroprusside and phenylephrine) decreased from 24 (22/26) to 0.00 (0.00/0.09) ms/mm Hg (P<0.01). The dose of isoproterenol that decreased systolic blood pressure (SBP) 12.5 mm Hg changed from 0.61 (0.51/5.3) to 0.17 (0.12/0.21) microg (P<0.01); the dose required to increase heart rate 12.5 bpm changed from 0.22 (0.17/0.41) to 0.74 (0.33/2.3) microg (P<0.01). The dose of nitroprusside required to decrease SBP 12.5 mm Hg changed from 2.3 (1.3/3.4) to 0.18 (0.14/0.24) microg/kg (P<0.01). The dose of phenylephrine required to increase SBP 12.5 mm Hg changed from 135 (110/200) to 16 (10/30) microg (P<0.01). We conclude that the efferent arc of the baroreflex can be completely interrupted with N(N)-cholinergic blockade. Estimation of adrenoreceptor sensitivity and sensitivity to nitric oxide donors by systemic administration of agonists is severely confounded by baroreflexes. Uncoupling of the baroreflex by N(N)-cholinergic blockade may be a useful method to obtain an integrated measure of adrenergic receptor sensitivity and sensitivity to nitric oxide donors in humans. This approach would permit the comparison of normal and abnormal physiological states without the "noise" of baroreflex buffering.

  4. The renin-angiotensin system and its vasoactive metabolite angiotensin-(1-7) in the mechanism of the healing of preexisting gastric ulcers. The involvement of Mas receptors, nitric oxide, prostaglandins and proinflammatory cytokines. (United States)

    Pawlik, M W; Kwiecien, S; Ptak-Belowska, A; Pajdo, R; Olszanecki, R; Suski, M; Madej, J; Targosz, A; Konturek, S J; Korbut, R; Brzozowski, T


    The inhibition of angiotensin-converting enzyme (ACE) or the blockade of angiotensin (Ang) AT-1 receptors affords protection against acute gastric mucosal injury, but whether the major metabolite of renin-angiotensin system (RAS), Ang-(1-7), accelerates the healing process of preexisting gastric ulcers remains unknown. Previous studies documented that Ang-(1-7) acting via its own Mas receptor exerts vascular responses opposing those of Ang II. We studied the effects of the Ang-(1-7)/Mas receptor axis on the healing rate of acetic-acid-induced gastric ulcers with or without the blockade of Mas receptors by A 779 and compared it with the effects of activation and blockade of the AT-1 receptor by the treatment with Ang II and losartan, respectively, the inhibition of ACE by lisinopril, the NO/cNOS inhibition by L-NAME and inhibition of prostaglandin/COX system by indomethacin in the presence of Ang-(1-7). Additionally, ex vivo metabolism of Ang I in gastric tissue was assessed by LC/MS method. At day 9 after ulcer induction, the area of these ulcers and the accompanying changes in total gastric blood flow (GBF) were determined as were gastric mucosal blood flow (GMBF) at ulcer margin and gastric oxygen uptake (GVO2). The gastric mucosal expression of mRNAs for constitutive nitric oxide synthase (cNOS), superoxide dismutase (SOD), and pro-inflammatory cytokines interleukin 1β (IL-1β) and tumor necrosis factor alpha (TNF-α) and plasma level of both cytokines were determined by RT-PCR and ELISA. The 9 days treatment with Ang II dose-dependently increased the area of gastric ulcers and this effect was accompanied by a significant fall in the GBF, GVO2 and GMBF at ulcer margin. In contrast, treatment with Ang-(1-7) which produced a significant rise in the luminal content of NO significantly reduced the area of gastric ulcer and significantly increased the GBF, GVO2 and the GMBF at ulcer margin. Similar GMBF changes and significant reduction the area of gastric ulcer was

  5. Blockade of CD47 ameliorates autoimmune inflammation in CNS by suppressing IL-1-triggered infiltration of pathogenic Th17 cells. (United States)

    Gao, Qiangguo; Zhang, Yi; Han, Chaofeng; Hu, Xiang; Zhang, Hua; Xu, Xiongfei; Tian, Jun; Liu, Yiqi; Ding, Yuanyuan; Liu, Juan; Wang, Chunmei; Guo, Zhenhong; Yang, Yongguang; Cao, Xuetao


    The migration of Th17 cells into central nervous system (CNS) tissue is the key pathogenic step in experimental autoimmune encephalomyelitis (EAE) model. However, the mechanism underlying the pathogenic Th17 cell migration remains elusive. Here we report that blockade of CD47 with CD47-Fc fusion protein is effective in preventing and curing EAE by impairing infiltration of Th17 cells into CNS. However, CD47 deficiency does not directly impair the migration of Th17 cells. Mechanistic studies showed that CD47 deficiency inhibited degradation of inducible nitric oxide synthase (iNOS) in proteasome of macrophages by Src activation and led to the increased nitric oxide (NO) production. Then NO suppressed inflammasome activation-induced IL-1β production. This lower IL-1β reduces the expression of IL-1R1 and migration-related chemokine receptors on CD47(-/-) Th17 cells, inhibiting the ability of Th17 cells to infiltrate into the CNS of CD47(-/-) mice and therefore suppressing EAE development. In vivo administration of exogenous IL-1β indeed promoted the infiltration CD47(-/-) Th17 cells into CNS and antagonized the protective role of CD47 deficiency in EAE pathogenesis. Our results demonstrate a potential preventive and therapeutic application of CD47 blockade in controlling EAE development. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. The effect of adhesion molecule blockade on pulmonary reperfusion injury. (United States)

    Levine, Adrian J; Parkes, Karen; Rooney, Stephen J; Bonser, Robert S


    Selectins are the molecules involved in the initial adhesion of the activated neutrophil on pulmonary endothelium. We investigated the efficacy of selectin blockade in a selective (monoclonal antibody RMP-1) and nonselective (Fucoidin) manner in pulmonary reperfusion injury. Groups of six rat lungs were flushed with University of Wisconsin solution then stored at 4 degrees C for 4 hours. They then underwent sanguinous reperfusion for 30 minutes during which functional measures (gas exchange, pulmonary artery pressure, and airway pressure) of lung performance were made. After reperfusion we estimated their capillary filtration coefficient (Kfc units g/cm water/minute/g wet lung tissue) using a gravimetric technique. Four groups were studied: group I had no reperfusion, group II had 30 minutes of reperfusion, group III had infusion of 20 mg/kg Fucoidin before reperfusion, and group IV had infusion of 20 microg/mL RMP-1 before reperfusion. Reperfusion injury was found between groups I and II by an increase in capillary filtration coefficient (1.048 +/- 0.316 to 3.063 +/- 0.466, p Kfc than group II (0.967 +/- 0.134 and 1.205 +/- 0.164, respectively, p < 0.01). There was no significant functional difference between groups II, III, and IV. Reperfusion-induced hyperpermeability was ameliorated by selective (RMP-1) and nonselective (Fucoidin) selectin blockade.

  7. Interleukin-6 blockade Improves Autonomic Dysfunction in Rheumatoid Arthritis

    Directory of Open Access Journals (Sweden)

    Ashit Syngle


    Full Text Available Autonomic nervous system (ANS involvement in rheumatoid arthritis (RA is well recognised and contributes to arrhythmia and sudden death. However, there is no study documented the therapeutic efficacy on autonomic neuropathy (AN in RA. This is the first reported observation of improvement in AN with interleukin-6 (IL-6 blockade with tocilizumab in RA. We report a case of 61-year old female with seropositive RA with severe disease activity, investigated for autonomic neuropathy. A battery of non invasive tests was used for accurate assessment of AN function based on assessment of peripheral sympathetic autonomic function and cardiovascular reflex tests. Tocilizumab 8mg/kg intravenous infusion at weeks 0, 4 and 8 was added to her treatment regimen. Cardiovascular autonomic function tests at baseline showed marked abnormalities of parasympathetic cardiovascular reflexes. After the first dose of tocilizumab there was a rapid improvement with normalization of parasympathetic autonomic activity with subsequent doses. IL-6 blockade with tocilizumab seems to have the potential to improve the vagus nerve mediated parasympathetic neuropathy and hence has the potential to restore cholinergic anti-inflammatory pathway.

  8. Effective dermatomal blockade after subcostal transversus abdominis plane block. (United States)

    Mitchell, Anja Ulrike; Torup, Henrik; Hansen, Egon G; Petersen, Pernille Lykke; Mathiesen, Ole; Dahl, Jørgen B; Rosenberg, Jacob; Møller, Ann Merete


    The ultrasound-guided transversus abdominis plane (TAP) block is used to treat postoperative pain after abdominal surgery. Abdominal wall sensory nerves are anaesthetised by injecting local anaesthetics into the neurofascial plane between the internal oblique and the transversus abdominis muscles. Sensory assessment of a TAP block may guide the decision on the extent of the block. The purpose of this study was to investigate if the dermatomal extent of sensory blockade after injection of 20 ml 0.5% ropivacaine bilaterally into the TAP can be assessed using cold and pinprick sensation. Subcostal TAP block was performed bilaterally in 20 awake patients scheduled for elective abdominal surgery. Sensory change in dermatomes T4-L4 was tested with pinprick using a blunt needle and cold disinfectant swabs after 10, 20 and 30 minutes. Data from 20 patients (40 blocks) were analysed. Eighteen patients registered sensory change after subcostal TAP block, and dermatomes T10-T12 were blocked after 30 minutes in all of these patients. Spread of sensory change to dermatomes T5-L3 was variable. This study confirmed that the dermatomal extent of a sensory blockade after a single-shot subcostal TAP block can be assessed using cold and pinprick sensation. not relevant. The study was registered at with the registration number NCT01024868.

  9. Coulomb blockade phenomena observed in supported metallic nanoislands

    Directory of Open Access Journals (Sweden)

    Wolf-Dieter eSchneider


    Full Text Available The electron transport properties of single crystalline metallic nanostructures in the Coulomb blockade regime have been investigated by low-temperature scanning tunneling spectroscopy. To this end, nanoscale flat-top Pb islands with well-defined geometries are grown on NaCl-covered Ag(111 substrate. The tunneling spectra acquired at 4.6 K on the Pb nanoislands reflect the presence of single electron tunneling processes across the double-barrier tunnel junction (DBTJ. By a controlled change of the tip-island tunnel distance, the spectra display the characteristic evolution from Coulomb blockade (CB to Coulomb staircase (CS regime. Simulations within the semi-classical orthodox theory allow us to extract quantitatively the parameters characterizing the DBTJ, i. e., the resistances, capacitances, and the residual charge Q0. Manipulation of Q0 is achieved by controlled application of voltage pulses on the Pb islands. Moreover, under specific tunneling conditions, the influence of the tip-island junction on Q0 is revealed in topographic images of the Pb islands.

  10. Extreme interplanetary rotational discontinuities at 1 AU (United States)

    Lepping, R. P.; Wu, C.-C.


    This study is concerned with the identification and description of a special subset of four Wind interplanetary rotational discontinuities (from an earlier study of 134 directional discontinuities by Lepping et al. (2003)) with some "extreme" characteristics, in the sense that every case has (1) an almost planar current sheet surface, (2) a very large discontinuity angle (ω), (3) at least moderately strong normal field components (>0.8 nT), and (4) the overall set has a very broad range of transition layer thicknesses, with one being as thick as 50 RE and another at the other extreme being 1.6 RE, most being much thicker than are usually studied. Each example has a well-determined surface normal (n) according to minimum variance analysis and corroborated via time delay checking of the discontinuity with observations at IMP 8 by employing the local surface planarity. From the variance analyses, most of these cases had unusually large ratios of intermediate-to-minimum eigenvalues (λI/λmin), being on average 32 for three cases (with a fourth being much larger), indicating compact current sheet transition zones, another (the fifth) extreme property. For many years there has been a controversy as to the relative distribution of rotational (RDs) to tangential discontinuities (TDs) in the solar wind at 1 AU (and elsewhere, such as between the Sun and Earth), even to the point where some authors have suggested that RDs with large ∣Bn∣s are probably not generated or, if generated, are unstable and therefore very rare. Some of this disagreement apparently has been due to the different selection criteria used, e.g., some allowed eigenvalue ratios (λI/λmin) to be almost an order of magnitude lower than 32 in estimating n, usually introducing unacceptable error in n and therefore also in ∣Bn∣. However, we suggest that RDs may not be so rare at 1 AU, but good quality cases (where ∣Bn∣ confidently exceeds the error in ∣Bn∣) appear to be uncommon, and further

  11. Dehydration kinetics of talc at 1 bar (United States)

    Ganguly, J.; Bose, K.


    Experimental results on the dehydration kinetics of talc, which is likely to be a major potential resource for water and hydrogen in carbonaceous chondrites, is presented. The rate of dehydration of an essentially pure Mg-end member natural talc, (Mg(.99)Fe(.01))3Si4O10(OH)2, was studied by measuring in situ weight change under isothermal condition at 1 bar as a function of time in the temperature range 775 to 985 C. The grain size of the starting material was 0.7 to 1 micron. It was found that the data up to 50 to 60 percent dehydration can be fitted by an equation of the form alpha = exp(-Kt(exp n)), where alpha is the weight fraction of talc remaining, K is a rate constant and n is a numerical constant for a given temperature. For any set of isothermal data, there is a major change in the value of n for larger dehydration. For up to approximately 50 percent dehydration, all rate constants can be described by an Arrheniun relation with an activation energy of 432 (+/- 30) kJ/mol; n has a nearly constant value of 0.54 between 775 an